We're on a well. The bathroom sink fills 1/2 gallon in 20 seconds, the sink takes a full minute! Much too slow! Might it be a restrictor? A pipe with solder blocking water flow?
Plumber charges over $100 an hour. Can I fix this myself?

Thanks for your response.

We're on a well. The bathroom sink fills 1/2 gallon in 20 seconds, the sink takes a full minute! Much too slow! Might it be a restrictor? A pipe with solder blocking water flow?
Plumber charges over $100 an hour. Can I fix this myself?

Thanks for your response.
Have you removed the aerator(see image), checked and cleaned the screens?