Hello, looking for any tips on clearing debris from a delta tub shower valve (single handle) as there no enough water flow. Water is insufficient flow for both the tub & shower.

I am on a well. In doing other work I had to shut down the pump. When the pump started back up I believe debris has gotten into the valve. Other sink water in this bathroom works just fine (along with the rest of the house).

I have;
A. Cleaned the shower head
B. Replaced the replaceable cartridge
C. Attempted to run a wire down the incoming lines cold & hot with little to no success (unable to get a wire in the bend)

Other issue with this shower-->Also this shower is making what I will cause a whinning noise after diverting the water from the tub to the shower head after a few seconds (not immediately). Thx in advance

you could try to flush the valve by removing cartridge and turning on water main quickly then back off.

Does the control valve have stops?

Take the large round plate off and see if there is a "nut" on the right side of the valve body. If so you have a "scald guard" and the balancing spool may be clogged with debris. This may not apply to your valve, however depending on what KIND of cartridge it uses.