Illness anxiety. Increased. please help.

I suffer from illness anxiety..even a minor change in body or symptom worries me a lot..i start googling it and it then turns out to be something more serious.. then again i feel stressed out and also there is a lot of negativity.i sometimes face pain in legs sometimes in arm sometimes in neck sometimes in shoulder, sometimes back..there's something or the other continuously going around in my mind..for last few days i don't know why and from where it came into my mind that near the right  chest above breast area there's something hard..i never checked earlier but for last few days this has started bothering me..i hv faced failure few times in my CA final exams and after that only this negativity has increased..please help..