If you're not in pain and your baby is gaining weight properly, this isn't a problem. But to make baby open wide so that feeding is easier for both of you, you might want to try a feeding position called "laid-back breastfeeding." This involves leaning back into a semi-reclined position (probably how you sit to watch TV) with good arm, shoulders, head, and neck support. Lean back far enough so that your baby can lay tummy-down on your body and make your breast available to her. Not only does this position eliminate the need to support your baby's weight through the feeding, but gravity keeps your baby's body pressed against yours, which triggers her inborn feeding instincts. What causes a baby to open wide is the touch to the baby's chin, which happens automatically in this position. Try it. It makes taking the breast a lot simpler.