well, I laid out in the shade all day at the beach on a rocky bank Fri afternoon. By sat morning my lower right hand side of my back was very soar. Sat I felt horrible all day long. The pain was not too bad but when I layed down in bed, just the pressure of my back on the bed caused great pain. I had to do melatonin and ibiprophin to fall asleep. That did not work so I had to drink 40 oz of beer ,, that did the trick. Sun morning was a bit better. I am 56 yrs old ,, never had this problem. Thank you :)