Hot water comes out in a trickle only in my kitchen sink, everything else is OK. The cold water has super pressure.

Turn off the water and open up ,the faucet. Pull out the cartridge and check and clean the inlet ports. Now turn the hot water supply back on for a minute to flush out the supply and valve body. You should have a strong stream of hot water when you do this. If not then click on back.
As a rule this is caused by minerals built up in the water heater being drawn into the system and clogging seats and inlet ports. This will occur if you don't flush your heater on a regular maintenance schedule. Let me show you how.
For long life and fewer troubles you should keep your heater clear of mineral build-up by FLUSHING NOT DRAINING on a regular schedule. Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run until the water runs clear. You will see a spurt of red,(rust) followed by white or yellow grains,(lime or calcium carbonate). This shouldn't take more then a few minutes. Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures that are affected . Now pull each aerator and clean the screens. Be sure you put them back together the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it. Hope this helps, Tom