What does it means if you have 50# in the static mode and 10# in the dynamic mode?

: : If you are in a house, on regular city water, then in most areas you will have a pressure regulating valve to set the proper pressure in the house. These valves do fail eventually, and one of the failure modes is the symptoms you describe.

: Buy an inexpensive pressure gauge; check the house pressure both in static mode ( no water running) and in dynaminc mode (one or more faucets running). This will help you narrow down the problem.

: If you are a novice, replacing the regulator is not a good first project to tackle. Call in a profesional.