Tingly left hand and a few other symptoms

for the past few days ive been getting strange tingly feelings and sort of aches in my left arm, im wondering if its a pinched nerve or something because i sit in a computer chair for hours on end usually with my left hand under my chin and my elbow jammed on the arm, also usually with my entire left side kind of squished into the side on the chair.

ive suffered from anxiety for the past few weeks and usually its because i have some symptom, look it up on the computer and hone in on things like heart disease or stroke, you know.. the really bad things. im 21, not super healthy, a bit overweight and i dont work out so much anymore. i had blood tests done and they all came back normal and an ECG that was fine too. i find that the more i think about my symptoms the worse they get. but the dizziness and sort of breathing irregularity seem to always be there a bit. i dont know if its from not eating well, being really bored and stressed, too much alcohol, the fact that i worry about everything or the hours i spend looking at a computer/tv screen.... i dunno. im just worried there might be something seriously wrong even tho i probably just answered my own questions. but please, if your reading this and you have any advice it would be greatly appreciated.