OH BOY I feel your pain! Tail bone pain is NOT back pain! Picture this, your tired at the end of a long day and when you park and get out of the truck you slip and land on that hard aluminum step. Right on the edge of that step and right on the crack of your #####. ( Darn near ripped the right cheek off) I did that about 5 years ago and couldn't sit,stand , walk or even roll over with out pain for for a LONG time!
After taking 3 days off (on the road) and a week or so at home I used a combination of round air filled dounut ( worked so so) and kitchen chair cushion and a piece of dense closed cell foam.
I used the foam and cushion together and some times seperate, the trick is to keep the weight off the tail bone and spread it to your cheeks ( no pun intended) Keep trying different things and combanations.
If your currently not a driver I'd wait till your better, if you have to drive I wish you the best.