Answer:
Just want to say, I am not a professional, and regardless of what i say you should bring this up at your next doctor appointment
Step-by-step explanation:
There could be many reasons and obviously I cannot diagnose you but this does sound like it could be some thing psychological, you are not faking it, however anxiety can give you horrible chest pain and digestive issues. The numbness sounds like depression or you dethatching yourself which opens the bot to tons of other things. You should probably get screened for depression because it is not normal to feel numb and lose interest in all the things you used to love. Poor mental health does make real physical problems within your body which is why you can get it checked out. I would say that the only non-psychological reason I can think of is growing pains but that wouldn't fit if you've been having it for 4 years.
Go see your doctor, if your parents go with you and they don't believe in mental disorders, ask them to leave the room and there is a very good chance that if they don't leave the doctor will have your back on making them leave. You should get this checked out. (:
I hope things look up for you and I hope I helped (remember I'm not a doctor)