Replaced hot water heater and now hot water pressure is drastically reduced at kitchen sink and bedroom shower only, all other hot water outlets are OK.

You probably got some junk in the lines.

Try this first:

Remove aerator on kitchen faucet. That's the screen at the end of the faucet. Turn on water full.

Remove the shower head and turn on into a bucket full force.

The latter one might be more difficult.

If that doesn't work, you may nned to remove the shower valve cartridge and flush.

You may have to do that with the kitchen too.

Try the easy stuff first.

Can't give KISS a greenie just yet but he's right on the money.

I removed the hot water connectors and didn't find any sediment or other junk anywhere, I flushed the line a bit and the pressure seemed to get a bit better.