Ouch, sounds painful! How is it now a few days later? In general, pain like that should be checked out. Clearly you hurt yourself when you fell. I have broken my tail bone and it is painful and moving makes it so. However, sitting? even worse. But you describe tingling which sounds like something may have shifted a bit and is compressing a nerve. But I, of course, don't really know over the internet so you should seek help from a medical professional. In the mean time, try ibuprofen to help reduce immflamation and then you can use a heat and cold approach (ice and heating pad). Also, try to gently stretch your lower back and gluteus maximus (butt). :>) Hope it is all better by now!