Many people suffer from chronic pain. You learn to live with it mainly because you have no other choice; you learn your triggers and try to avoid them, but some triggers (like weather or calendar events) cannot be avoided. And sometimes your pain decides to flare up on a holiday.
I get migraines. I got one on Christmas; it was really rough. My amazing husband helped me through it, and I have some medicine that allowed me to be mostly functional, but it was still a hard day. You are supposed to be happy on Christmas, and everyone else was happy, and I had every reason to be happy, but I was not; I was in pain. I am grateful that I was functional enough to get out of bed and try to enjoy the day - going to the in-laws' house, seeing family, opening presents - but I was not all the way present. I had to excuse myself a few times to go to a quiet part of the house and turn off some lights and try to unwind, hoping that would make the headache release but it did not. Thankfully the migraine went away the following day so I was able to engage with family for the rest of the weekend.
If you suffer from chronic pain, know that you're not alone. Some can hide it better than others, but many are fighting that battle. Speaking about it can help; also reaching out to someone close to you can be beneficial. Remember to take care of yourself.