Had it, it sucks. Had to go to physical therapy for a few weeks and take some time off from softball. RICE it. If you want to keep playing a compression shirt or sleeve might help.
The best was seeing some hippy dude in jeans and socks with sandals. Not sure if they pulled him out of the bleachers or what but he damn near ran outta them flip flops every damn time he chased down a fly ball.
If you can manage buying a few different bats get them in different weights and at least one balanced bat and one endloaded bat. Everyone can find what works for them.
Seems like more of a chance of getting ripped off on those facebook pages as well. See a lot of guys throwing around horror stories of NGTG douchebags.