Growing older is a learning experience if only because you have expanding opportunities to discover what can go wrong with the human body.

My latest learning experience occurred at my brother’s house in San Antonio, Texas, toward midnight on Thanksgiving. I had feasted on a wonderful mix of American and Lebanese dishes sandwiched between two glasses of wine. We watched a DVD, and I felt good. Just before midnight, I became sleepy enough to go to bed, so I did. Somewhere between the couch and the bedroom, though, the left side of my torso imploded.

I tried to read myself to sleep, but was seized with spasmodic pain and couldn’t find any position that didn’t hurt. The pain seemed to be centered on my left shoulder blade and radiated to my rib cage and lower back. Even my left arm hurt.

I began to wonder if I was having a heart attack.

After 15 or 20 minutes of not getting any better, I used my mobile phone to call my brother, who gave me ibuprofen, a heating pad, and reassurance that I wasn’t having a heart attack. An hour or so later, I felt well enough to try to sleep on my right side, and did — but not very well.

On Friday, I spent two hours with a massage therapist, who gave me a beating I still feel.

It’s Monday, and I have muted pain, numbness in my arm, and an occasional spasm. What is it?

A pinched nerve. I didn’t know that a pinched nerve can cause muscle spasms. Now I do. I’m here to tell you that you’ll feel each one, even as they occur on top of one another.

I’m mystified by what caused or aggravated it, but I’ll never know.

I’m thankful that it wasn’t a heart attack. I’ll be thankful if heals and never happens again. That is too much to ask for, I’m sure.