[Johnc]

Do you have the black Headhunter pump? Your pump may have some 'scale' build up on the impeller. Fairly common in hard water areas. There is large screw in the center end of the fat portion of the pump that allows you to manually turn the shaft. You might try moving the shaft in both directions to free the shaft. Also, Headhunter often offers pump owner's some really good deals on direct exchange pumps.