This could be caused by a few things: 

1. The frame is sitting too low. You need to wear the frame on top of your hip bone, this will put the lumbar pad in the small of your back.

2. The weight on the frame is sitting on the bottom of the frame. Try to evenly distribute the weight and get the heaviest part close to your shoulder blades. 

3. The delta straps (run the from the center of the belt to the pack/frame) are too tight. Having these too tight can cause pressure and they will need to be loosen. 

4. The stay curvature is incorrect your back profile. We offer other options if you'd like to try these out then return which you do not use. 

If you have tried troubleshooting, feel free to reach out to our customer service team. Email is best as you can include photos of you wearing the frame so we can see how it is sitting. We can recommend changes and alterations accordingly.