Arm,stomach,back pain

Patient: Ok so im 18 years old and for about three days ive had what was thought of as constipation but ive never felt like this so idk if it was really constipation or not. My whole left side was in a dull pressure so I was told to take a laxative, ive never taken one before and after a few hours it worked and it was (sorry for the disgusting description) watery and green with brown in it but I saw just the teeny tiniest bit of red spots and I got freaked out, after using the restroom a few times I saw a tiny bit more red spots but then the rest of the time I saw nothing so I thought that was flushing my body. The pin in my left side went away a bit but i feel a bit nauseaous when i drink water or eat but i do keep it down and idk what that means… then I had a bad pressure feeling in my right arm and it went up to my shoulder when I breathe in it kinda hurts but that’s when I take a deep breath. My parents said it was a pulled muscle but im not sure…I sometimes have pressure in between my upper back right between my shoulders that sometimes feels like a warm feeling and idk if that is because of how I lay or stand or sit because these come on randomly. I have a dull ache pain in the middle part of my right side and I have no idea if that has anything to do with kidneys or gallbladder…im big and i don’t know whats considered overweight but it all just started happening and im scared its something serious, if its just me stressing or maybe a pulled muscle or bad posture that would relieve my worries sooo much