Thanks for the update. The check valve at the bottom of the well must be fixed or replaced to stop this kind of water hammer. Sometimes just removing the above ground check valve makes the bottom check work and solve the problem. In many states an above ground check valve is illegal, as it can potentially draw contamination into the well. Other states have not figured that out.
In Texas they say you must have a check valve above ground, but you cannot cause a negative pressure on the underground line. This just shows how little our government officials understand about their jobs. An above ground check valve CAUSES negative pressure on the underground line. So you cant have it both ways.
Most people just put a second check valve as a safety for when the bottom check fails. What they should be doing is eliminating the pump cycling, which is what causes check valves to fail. Glad you got it fixed, but if you still have an above ground check valve and your pump is still cycling on/off repeatedly, you will soon have the problem again.