How would i know if this is my appendix or a sore/pulled muscle?

Different: Appendicitis can start with mild pain around the belly button. The pain worsens over time. It can become sharp with loss of appetite, nausea, vomiting & possibly a fever. The pain usually moves toward the right lower quadrant of abdomen. Bouncing or jolting will often make the pain worse. Appendicitis can have varying presentations. If you have severe abdominal pain it is best to go to er.

Severity of pain: Appendicitis usually causes severe pain, especially with movement. The pain may start in the right lower abdomen and move to the central abdomen. There is often nausea and vomiting. The pain worsens over a period of a day or so, it is constant and never goes away fully. Aspirin or tylenol won't help much. Any question, get it checked out.