Why does my tailbone stick out and it hurts when i lie on my back on a hard surface.?

Skinny?: U must b thin. Ur coccyx may b the cause. If it isur tailbone it is at the very end of ur spine(tail). If this is it, it can b excised. If it is above this it can b ur sacrum & not much 2 do.If the coccyx only bothers u when u lie on a hard surface don't do it or use a cusion. If is bothersome more then that & effects ur adl's seek a surgical consult. I= 45 excisions & all r happy.