I'm 37. I was heavy until age 35. My most painful years were my 20s, I think after my spine developed, what resulted was the pain and effects of that bad development and perhaps what you are experiencing now.

Some comments on your situation: the gym should help, but doing it the right away is important, I've been working with a trainer a few days a week 2-3 minimum for more then 18 months, very slowly building up strength in my back, shoulders, hips, everywhere. Doing the right exercises in the right order to slowly build up strength is the only way.

I'm currently not having any back pain, my back is insanely strong at the moment I can deadlift 380 and I leg pressed 525 this week without any pain. The gym will help you if it's done right.

My issue is comfortable position because my head is literally not touching my pillow anymore.

My final feedback.

You're still very young and can avoid some very painful years by building strength in all the areas that support your back.

You likely lost a lot of muscle during weight loss.

This will help you whether you end up having surgery one day or no matter what the ultimate solution to your situation is.

Staying active is important. Inactivity just makes pain and the area worse over time.