Hi Blondie.
I speak from experience here, so one of my top tips is, Dont search for any information on the web, or in books on any small aches and pains you have,'cos WOW can that blow things up out of all context of what is wrong. I seem to have developed what they call "repetetive strain injury" (tennis elbow) down my left arm. course you look that up on the net, you get heart attacks. i think part of this condition is that we worry too much, and have to find something to worry about, and so we ignore common sense, and aim straight for the worst news. Its just all part of our condition i feel. When you've had this for a while, you'll realise what muscle tension can do to you, its harmless of course, but can cause headaches, backaches, shoulders, leg pains. The list is endless. also something else i've noticed too. because of the tension in our muscles, they are less flexable, and when you do a bit of excercise, you pull muscles, and hamstrings a lot more than you would normaly. The muscles can get so tense that they dont have the give in them as before. I also think that at 15yrs old you are probably fitter than any of us old codgers on here. you just try to relax, you'll be fine.
Best wishes
Mudslinger uk