Chest, Back, neck pain. Help me alot.

I'm 17 and i have been going to gym from past 1 and half year.  My back (mainly lower )used to pain. But the pain was normal. And sometimes there's a pain in chest (left side)  for a 1-2 second. and chest pain was very rare. And 3-4 months back my chest pains alot, then i took medicine from doctor and after 2 days i was good. But now from past 1 week I'm suffering from intense lower back ( full spine)  and chest pain. My neck also pain. I can walk but while sitting and bending my lower back and neck pains. I'm not going to gym from 1 week. but still I'm suffering from pain. I have visited a doctor and he gave me medicine and said that the pain is due to exercise. But it's been 1 week and I'm still suffering from it. Please if you can help me or give me any advice it will help me alot.