This is a more common problem than you may think. Plus, it is good that you want to fix it because you cannot shoot your best when you are not comfortable. Holding you head up will produce poor shooting, you must have firm cheek weld.
The first issue is making sure the eye relief of the scope is set for the position you intend to shoot. When you hold the rifle, with eyes closed in your nature holding position, there should be no "shadows" in the scope or strain on your neck. (This assumes you have already adjusted the eye piece to give you a clear crisp view of the reticle)
Firm cheek weld is essential without neck strain. The comb height needs to be adjusted to match your body profile, so you have a solid cheek weld with your eye aligned with the center of the reticle. Sometimes this has to be worked into comb with the scope eye relief adjustment.
Experiment with different positions, eye reliefs, and comb heights until you find one that is comfortable with a complete and clear view of the scope. Here is where an experienced mentor can help. Have the mentor observe you and make adjustments while you are the position you intend to shoot.
Sometimes, the length of pull on the stock is either too long or short depending on your body profile. This may need adjustment.
For your best performance, this needs to be fixed so don't give up. Perhaps other members can offer additional help.