If the gun was shot with the action screw loose, all those can happen. Check and see if the wood is cracked inside, where the recoil lug fits into the stock, that may be why it shifted back and touched at the tang, cracking that. The wood needs to be relieved at the back, and probably bedded under the lug to help take the recoil. The reason it cracked is the tang is touching the wood, it should not touch there, the recoil lug under the front of the action should be taking the recoil.
First off, don't shoot it until you fix the bedding of the stock.
