How about teeth? When DS started teething, he refused the side that was most uncomfortable for him to nurse on. If that's the case, it will pass. Otherwise, it has been suggested to me (though thsi might work better with youngerr babies) to start on teh preferred side, then after it starts flowing, take them off and slide them over to the other side w/o really changing position...just slide across your lap, kwim? may not work since he's older, but worth a try.