Healing basically involves circulation, getting the old stuff moved out, making room for the new to come in, whether it be liquids, energy, whatever. You may not be able to completely heal something with massage, but you can clear the way for it to heal itself. Mainly massage is about awareness, just shutting off the chatter in your mind and opening your senses as much as you can to what's happening in the body in question, and perhaps in the surroundings too.
I am not a doctor, nor an expert, use all of this advice at your own risk. Just be careful, go slow, and displace that chatter in your head with focus on the task at hand.
some useful techniques for self-massage:
Right-handed people sitting at desks tend to build up tightness and fatigue on the left side of the shoulders, as these are the ones that anchor the spine from falling to the right. While the right side stays active and circulating, the left just cramps up. (We also tend to sit mainly on the left hip bone; gotta get that right hip down, and keep your feet on the floor, not bunched up under the chair. And drink some water once in a while, lose those de-hydrating sodas.) The muscle that runs along the top of the shoulder is the trapezius; when it gets tight it can actually pull the associated vertebra out of line. To loosen it, reach your right hand across the front (elbow on chest), and put the side of your thumb on the front of it, then slowly trace it into the neck, where it tapers down to a tendon; stay on the front of it as it merges into the neck muscles. Then, reach down the back side of the muscle with your other fingers, grab some tissue, and pull it up toward your thumb, rolling the tissue back and forth over itself, like kneading dough. It hurts because it needs attention. Breathe into it.
For the top of the neck, put your hands behind your head, and knit your fingers together, then dig both thumbs into the sides of your neck. Without your fingers knit, you have to use all the muscles you're trying to work on to exert the pressure; with them together, all those muscles can relax. It works even better if you're laying on your back.
There are jaw muscles going along the sides of your skull, above your ears, just below the ridge along the side. Click your jaw together a little and you'll feel them. Make fists and grind your second knuckles into them. You'll be surprised at how much tension you were carrying in that thin little layer of muscle.
For your lower back, make a fist, put a knuckle into your lower back, and then, very important, bring your other hand around to grab your fist. This gives you way more power than using just one hand, and puts far less strain on the front of your shoulder. Grind away, twist your fist into it (careful of the kidneys), getting down around the tailbone and into the hip joints even. You can try it laying face down in bed, but put a lot of pillows under your hips and chest so you don't jack your lower back.
Arches of feet: on carpet or something soft, roll a foot onto the outer edge, and then on over, so most of the bottom is pointed upward. Dig your other heel into the arch. oh that's so amazing...
Calves: this takes some practice, but it's amazing, and can make a long walk easier to get through. Sit (or crouch down on one knee), with the knee directly over the ankle, i.e. calf vertical. Tap your fingers on either side of that (relaxed) calf so that it jiggles side to side. As it is, that's going to feel good, but if you can figure out how to really get on the resonant frequency of the tissue, you will feel it, it starts to REALLY jiggle. Easier to have it shown to you, but if you practice, you'll get it. You can do the tapping near the bottom of the muscle to move the top part. You just have to make sure the calf is loose, not engaged, otherwise you won't get the full effect.
Thighs: similar action, sit well off the chair so your whole thigh is free, then put both palms on either side of it, just behind the knee, fingers pointed down, and vigorously alternate moving them up and down, to shake the part of the thigh closest to the chair. Figure out the right speed/intensity to make it really jiggle. Then, move your hands to the end closer to the chair to jiggle the part nearer your knee. It takes practice to get the jiggle to really take off, but it's pretty incredible. Try doing these moves to just one of your legs, and later that day notice the difference between the two.
All of the above techniques work great on others. When working on others it's very important to learn to ground yourself, just keep the energy moving through you without judgement, and let it flow right on past, emptying into the welcoming earth below and all around you. If you're standing, try to keep your hips under your shoulders; it's far too easy to get bent off balance and end up straining yourself. And keep breathing, all the time, especially when you are exerting, no holding the breath. Make sure they keep breathing too.
Ask for lots of feedback, higher/lower, harder/softer, up and down/side to side, a hair left, etc. Muscles that won't take any pressure in the beginning will sometimes take a lot more after they warm up some. Mainly at first just explore, nothing too deep, and gradually work your way up to some intention.
On the shoulders, work from the outside in, roll the tissue between the sides of your fingers and the sides of your thumb (the first knuckle distributes pressure more evenly than the tip, and because it's closer to the hand you can get a little better leverage). The big muscle on the corner is rarely sore, and is easy to get good and loose, making room for other tension to drain. For the top of the neck, gently encourage them to lean their head back a little, and keep it completely supported (be very very careful), and work into the joint at the top where the skull attaches to the neck. Unless they're tipping their head back a little, these muscles will be engaged and too tight to work on much. One hand can be under the jaw, and the other can be digging into the top of the neck, both lifting and supporting the head.
For most muscles, think of a bunch of spaghetti going in the direction of the tissue, and you want to roll the strands against each other, making the inside of the muscle massage itself, rolling over itself. Again think of how you knead bread, the top sliding past the bottom, the inside shearing and stretching.
Elbows can work great on backs, but you have to be very careful. You want to use your weight, not your muscles, so your shoulder needs to be directly over the elbow. Until you know what you're doing, use the thumb and first finger of your other hand to make a ring around the tip of your elbow to stabilize it; what feels great reaming away on one spot might feel really horrible if you abruptly slip even a quarter inch to the side. Don't make it worse, first rule....
For back muscles, this is so great, and way safer: the receiver sits on the edge of the bed, elbows socketed into the little hollow behind the knees, all of the weight of the upper body resting there, back disengaged from holding itself up. The giver lays on his/her back, and uses the big toe, the ball of the foot, and the heel to just mash it up. If the receiver wants to push back, use your feet, not your back muscles. With this technique, a tiny person can give a huge person all the pressure they could ever wish for.
Walking on backs is also cool, as long as you avoid the kidneys and the two lower ribs, which are floating and easy to snap. Seriously, be super careful or just don't do it, but if you pay attention, a big person can walk on a small person's back okay. Position yourselves so the receiver's waist is next to a doorframe, with a little pillow under the hips. The giver keeps both hands on the doorframe, fully stabilized, get it? One foot stays on the hips (on the hip bone, out of the lower back muscles), and you shift your weight on and off that foot onto the other; dig the toes under the shoulder blade, push the big toe deep into wherever.
For me, when receiving, "OW" and other screaming and thrashing generally means "yes, right there, just like that". If you like it vigorous, be sure to establish which words mean stop, and which ones don't. Breathe into the pain, hurts so gooood.
Learn some basic Yoga and your muscles won't hurt so much. My achilles tendons used to be unbearable until I learned to walk properly, now they almost never hurt. And drink some water. And BREATHE!!!!