I felt some resistance when turning on the hot water at my bathroom sink yesterday. When the water started flowing there was very low pressure. The cold water is fine.

I disconnected the supply line and turned on the water to find what appeared to be obstructed flow out of the wall.

I don't have any experience troubleshooting plumbing issues residing before the local shut off. Is there anything I can do short of calling a plumber? Thanks!

Kevin