Acceleration is one thing to test. Beyond that, it could be your IP or your routing. I just tried CNN, MSNBC, TVLand, TNT, SYFY and A&E East, and there was no buffering or freezing on any of them. I wish I had better news. You can try a VPN to see if that helps.
If all US channels were freezing today, you would see a raft of people reporting that today and that is not the case.