Learning self-care is a core life skill, especially if you've grown up in a family rife with neglect, like I have. When applied consistently and based on medical knowledge, self-care becomes a legitimate first aid that increases comfort and prolongs the lifespan.
Panthenol is a B-vitamin precursor, available as an over-the-counter ointment. It's supremely safe in any dose and you should be slathering it on non-bleeding skin injuries. A dermatologist even told me to rub it on the tip of my penis. Seriously, give your buddy some attention and don't be a jerk.
Olive oil and aloe vera are of tremendous help, especially with burns. I got a serious boiling oil burn on the back of my hand, but I resolved it with a traditional ointment that involved — olive oil. Again, both olive oil and aloe vera can go on your penis. Don't doubt it, just do it.
Immense stress can cause muscles to cramp up. In my case, the constant "grit my teeth" mentality caused me to literally pulverize my teeth. The solution is to remind myself to unclench the jaw all the time. I felt immediate relief and my facial muscles relaxed. My voice also relaxed and I felt it go deeper. It could be a good idea to do a total muscle relaxation before bed, going through muscles one by one and checking if they're tense.
When sitting down, standing up or doing any major motion of the body that involves shoulders and knees, make sure the weight doesn't suddenly shift from one part of the body to the next. Whenever I feel my back or shoulders hurt, I know it's because I haven't been paying attention. I sloooooooowly get up and sit down until I find a method that doesn't cause discomfort or pain and then I speed it up if possible.
Avoid collapsing in your chair or on your bed. Instead, learn how to gradually settle and your body will adapt as needed, without much pain. Fully support your neck and your spine when sitting or laying down. When getting up, don't jump up but again gradually support your spine with your hands and lift with your knees. Make a conscious effort to move your body and you'll feel the tension disappear.