What Causes Severe Pain In Buttocks On Sitting For Long Durations?

This might sound weird but When I was snowboarding last weekend I crashed and got jabbed in the but by a dead tree branch. It hurt to sit down for about a day. It felt like it got better. I went to the gym and did some dead lifts. It now hurts really bad to sit, get out of the car or to cough and sneeze. I don t know what s going on? Help