I have hot water through all of my hot water pipes through the house except the hot water faucet in the shower, the water will be hot when you first turn on the water and then will turn to warm within a minute and will not get hot. When we turn on the hot water faucets in the sinks the water will get hot and stay hot. I am at a loss as to what to do or look for.

Sounds lioke the hot inlet on your mixing valve is clogged with junk. One handle or two, and a brand and model for the valve would help a great deal

Two handle valve - can not found brand must be off brand - pulled valve out replaced washer could not get seet out to check still having problems

Pull the hot stem again and cver the opening with a tightly held towel. Have someone else turn the main on for a moment to flush the lines and then off. Did you get a strong pulse of water into the towel?