Most pitching issues are caused by one of two issues:

Take a series of 3lessons just on pitching the ball. Most pitching issues are caused by one of two issues 1) a break down of the hand and wrist action at impact, that does not allow you to hold the club face square and with its true loft. Many people call this hold the club open at impact. 2) Body movement either up or down with create very inconsistent pitching, with both fat and thin shots.