There are a few reasons why your breast feeding experience may be bothering you. Are you and baby in a comfortable position? If not this causes baby not to latch on properly and increases unnecessary pull on you. Many moms comment that the football hold is the best. In this hold you turn the baby to where their feet is under your arm facing backwards, with their head and body cradled by your hand and arm. This allows you easier movement of your other hand to help position baby easier. Many women with larger breast find this position more comfortable. You want to be sure you are in a relaxed position before beginning as stopping before having to switch breast only causes baby to get fussier and it is harder on you.
Never be afraid to ask advice from other moms and your doctor.