For short periods of time, prescription medications (such as narcotic pain medications or muscle relaxants) may be helpful to alleviate pain or related complications.
It can take anywhere from 4-10 hrs. now if your head gasket is warped you will have to take it to have it milled that takes from 1 day to several days. if not you can just buy a completely new one that fits perfectly for about $150.
There's no way to tell that a cylinder head is cracked without actually taking the head off the block. It could be warped, or it could be the gasket alone. You're looking at 500 for a salvaged cylinder head, 100 for the gasket set, and about 700 in labor and materials (i.e. anti-freeze).