Hurts to contract pelvic floor muscle, sharp pain in pelvic floor, pressure on it or coughing hurts and it started after trying sit ups. what happened?

Pain after sit-ups: It sounds like you may have strained a muscle while doing sit-ups. Anti-inflammatories like Ibuprofen can help with the discomfort. If your pain persists you should see a doctor.

You probably: Strained a muscle and it should settle down.

See below: You may have developed a hernia or muscle tear. The best way to find out what it is would be to talk to your doctor.

Pulled muscle: Most likely its a pulled muscle but a rare possibility of hernia is also there. Anti inflammatories , seeing a physiotherapist and avoiding sit ups and if symptoms are still persisting see a doctor . Gradually introduce exercises after pain has gone away completely otherwise they can come back with vengeance.