low water pressure

I have a bathroom sink that when I turn on the hot water, it sounds like a jack hammer, rattles the hot water line and only a trickle to no water comes out of it. The cold side works fine. No other faucets/toilets in my house have this problem. At one time, I had a similar problem where at the point where the main line came into my house, it made a thumping noise. So I installed something on the line which counter-acted the pressure (sorry, I can't think of the name). This took care of a majority of the thumping issue. Should I install something like that on the bathroom faucet line? Is there too much pressure in that line? Maybe there's a way to equalize it? Thanks, Kevin

Hi, A plumbing friend is going to help me replace the tub in my bathroom, we've been planing this for awhile. I'm going to start demo in the bathroom in the next several weeks, set the tub & he'll come in & finish. He just left me a voice mail tell me I should buy a Citation Waste & Overflow unit in brass. Unfortunately, I won't be able to get a hold of him for 2 weeks, he's off on vacation. Is this a brand? I did a quick web search & couldn't find anything, I'd like to know a bit more before I go to a plumbing supply store. Thanks, Bob