If your sprayer is the type that cuts off the faucet flow when you press the sprayer trigger, then it could be the transfer valve is stuck due to corrosion or mineral buildup. The transfer valve is an integral device usually located at the base of the spout swivel. If you have a two handle faucet, the spout may have a threaded attachment that can be unscrewed to access the valve. After removing as much water as possible, pouring a little vinegar or coffee pot cleaner into the swivl area may help free the valve up. You may also be able to push it down to help dislodge any material that may be jamming it. If you have a single handle faucet, the handle assembly may need to be disassembled to remove the spout.