Boy do I need help! In my master bath I have 2 sinks and a shower one sink and the shower have all of a sudden developed low hot water pressure. I have changed out the cartridge in each and still have the problem. What is the next step? Please help.

When you had the valves open did you turn the water back on for a minute to see if you had hot water pressure and to flush out the supply and open valve body? If not then do it and get back to me. Good luck, Tom

Remove shower head, clean flow restrictor. Also, remove aerators from each tip of your sink faucet and clean them.