I Believe I Have Strained Many Muscles In My Back

I believe I have strained many muscles in my back and front torso. It feels under the breasts that I have been punched a few times and in the front lower stomach the same. The tip pain in my pack is more pain not like a punch and lower back sore and painful. I did lift a very heavy . My sister thinks it's a heart attack but I don't Can you help in anyway or is this too vague?