Had clogged up kitchen sink. Plumber used snake to clear. He also fixed leak at pipe under sink. Now hot water pressure lower and very noisy when using hot water. Sounds like water is running through pipe on other side of kitchen, but it is actually just the noise of water running from sink to pipe underneath. No problem with cold.
Can anyone explain? Didn't notice problem until plumber left.

He my have left the isolation valves under the sink in a different position than you are used to. Gently open them both until they stop, then 1/4 turn in the "closed" direction. Loosening the packing nuts under the valve handle may make the valve esier to operate, loosen them no more thsn one turn. Be sure to "snug" them back, after.

Hello, It could be that the new supply line to the faucet may have twisted or kinked when your plumber tightened the nut. Check to see if the line looks curled up, or kinked. It should have a smooth look to it. Also make sure that the shut off valve is opened all the way. Goodluck-------Zeke

Check out Zekes solution first. If there's no kinks in the supply then I would suspect that when he was working on the supply he might have dislodged some crud built up in the pipe walls and it 's now blocking the hot water inlet port of the cartridge. The solution to that would be to shut the water off at trhe stops under the cabinet and open up the valve. Check and clean the inlet ports on the cartridge and before you reassemble turn the water back on for a minute to flush out the supplies. Reassemble and test. Better
Now? Good luck, Tom