I have a tight pain in my upper left chest, just above my nipple. ive also recently been waking up with cramp in my lower legs. and waking to urinate.

Get eval: At 19, with Chest pains, leg cramps and Increased urination in am it would be best to get and eval and some routine labs, including a Urinalysis as well. best wishes.

Muscular chest pain: You're young so it's likely muscular chest pain. I would stretch your chest and try not to exert yourself to much that would cause you any discomfort. When reading this at first I was concerned for cardiac chest pain until I saw your age. Best of luck and feel well.