If midnightsun's on track and the person in the OP's post isn't able to resolve the issue by packing and repacking to shift the weight/center of balance, look at Aarn packs.

If you click through to my website below and select gear reviews you will see that I am in the middle of testing one, as are two other people. I've seen in various forums questions about these packs and whether they work as advertised. The pack seats the weight on your hips quite firmly and the center of balance shifts lower.