How do you study when your physical body kinds of stops you?

Personally, I like studying for long hours consistently instead of going into breaks since it provides higher concentration

But unfortunately my physical body doesn't allow me to do so. Lately whenever I sit for around 20 minutes my neck starts to hurt, along with my upper back

It is so frustuating. I know I mentally prefer studying for hours but my physical body just don't allow that which resulted in me having to lay down and take breaks.

The thing is, as I take breaks I got distracted and procrastinate.

I am someone who gets procrastinate very easily though if I am motivated enough I'll be able to get into long study sessions

How do you stop it? Like is there a way to endure the neck pain or a way that I can fix this neck problem?