Q: I know it might be hard to answer this question but what causes a pull hook? and is there any drills that might cure this problem?
A: We have all seen photos of Tour players after impact with their arms extended. At impact the arms are not fully extended but should be at a point 3-4 feet post impact. Commonly, the shortening of the arms and the weight remaining on the back foot causes one to pull hook the golf ball. We shorten our arms to avoid crash landing the golf club into the ground. Two things need to improve.....your arms and your weight shift forward.
Drill # 1: With a short iron make a normal backswing and abbreviate your swing after impact to finish with the club at waist high pointing to the target. It's going to feel like a punch shot. This will help you lengthen your arms, check the clubface to ensure that the leading edge is vertical and gets you off your back foot.
Give that a try and report back.