Sometimes, when i sit down, my tailbone hurts a lot, and i feel a little "crack" in it. is it normal or should i be concerned?

It will get better: Tailbone pain, or coccygodynia, is commonly caused by trauma, and its probably the hardest problem for me to treat personally. It's hard to access the area so there's little to do but that also means that even if there is a fracture or subluxation, usually we recommend patience and activity modification (stand more and use a cushion for sitting). No casts, no injections, maybe an antiinflammatory.