I just installed a single contol tub and shower set by price pfister and when I Turn the water on I am getting cold water and warm water and no hot water what did I do wrong

Was there an integral stop on the valve or individual stops on the 2 supply lines? Most likely cause is debris got into the hot inlet during your install. You can easily dislodge junk shutting down lines and opening connects. Is this a cartrdige, shut down the main and pull the cartrdige. Back to you