General comment...

don't ignore pain, especially severe pain.

Pain is caused by something.

It is important to ascertain what that cause is. Absolutely important!!!!

When the cause of pain is unknown and continuing...

in general, some meditation and breathing exercises may help. By help? Oh, I mean, with serious pain? Looking at maybe 5% or 10% pain reduction. But, also, generally, might also help with a better ability to endure pain.

I have dealt with high levels of pain and am dealing with high levels of pain. One thing I have done...and I have not had this confirmed by anyone...is, oh...in winter, sometimes I will go out with lighter coats. Or if I have to endure some pain hammering away at some woodwork, I will hammer a bit longer. It is my amateurish attempt to get my body ready to endure higher levels of pain.

I know that boxers do this in training. Muhammad Ali had his sparing partners, work his abdomen hard so that he was more accustomed to handling pain levels.

I don't know any professional confirmation of this technique. But from my own experience, it has helped some.