Hi, It has been recently colder than normal in Texas. Every sink and shower has running hot and cold water running except the master bathtub and shower. The tub is the only one that has running cold water no hot water (it only trickles) and the shower doesn't run any water at all. Could the issue be a frozen pipe? It was running perfect the day before. We turned off the main water encase it was a pipe and have a brand new water heater. Help what can the issue be??

Are the valves to the tub and shower in an exterior wall?

If you get a trickle of hot just let it run for 15 monutes. If it was a frozen pipe it will be flowing. If no flow then a clogged hot inlet in the valve or stop