Pain in the Ischium after falling from stairs

Patient: I fell on our wooden stairs, 4 steps down. Looking at the skeletal system drawing, if I am not mistaken, the one that hit the stair is the ISCHIUM. Before going to bed, I administered cold compress. After more than a week now, I can still feel a little back pain, an inch or two, above my butt hole. Does it really take long before the pain goes away? I’m sure I did not break a bone. Is the ischium connected to the spine? Need I see a doctor?