So i've been doing push-ups lately and i've noticed a sharp shock sensation up my arm sometimes. it's very annoying. i am healthy too. what is this??

Strain vs sprain: It's very possible that you strained a muscle and/or ligament OR sprained a ligament by overdoing things or perhaps from poor technique. Use RICE (rest, ice, compression & elevation) for now plus OTC pain relief eg ibuprofen OR naproxen and/or acetaminophen. See your FamilyDoc if no better in a few days to weeks, sooner if numbness/tingling/weakness or redness/swelling.