Hi!
Summary: I've had pain similar to that described by others, plus more pain. I'm now in the process of receiving diagnoses. Here's what's happened.
Out of the blue, 2-3 months ago, I woke in the middle f the night with a strong ache in my back. It felt exactly as if the muscles either side of my back were strongly tensed up - contracted. I couldn't relieve this by stretching, and it didn't make a difference whichever way I tried to lie. My back was made very stiff and uncomfortable by this and only gradually subsided once I was up and about. By the afternoon, I was perfectly fine. I'd go to bed in the evening feeling great but wake in the early hours tense and stiff again! Very mysterious. I had the same bed for two years, from new, in perfect condition so it's nothing to do with that.
I guessed that I'd pulled or compressed something in the gym with a new exercise, so I experimented by omitting one exercise in turn. This didn't suggest any conclusion and the intense ache arrived some nights, recur for a few nights in succession, then later be missing for several nights in succession. Odd.
After a few weeks of this, I coincidentally moved addresses, leaving my own bed behind. In my new home, I initially had no problem. Then the ache arrived. Then the ache went away but I started to wake in the early hours with a severe pain in a specific part of my spine. It felt as I imagine it would feel if a knife was stuck in my back! And I was almost scared to move. But one has to get up sometime, so I'd get up each morning in agony, pushing myself up very carefully and slowly from bed. I'd be in this pain, and find it painful and difficult to move my spine for a few hours. Finally, as with the other ache, the pain would subside helped by sitting with good posture or walking. By night-time, I had only an ache.
Having the ache AND then such pain prompted me to book an appointment with an orthopaedic surgeon. In the meantime, I changed beds. In the other bed, I had no trouble. Over a period of 6 or 7 days, my ache subsided so when I saw the doctor I felt only a very slight localised ache and felt great.
I keep fit, do some weights, and run and I'm in great nick for 44. The doctor checked me out, including twisting me to see how flexible I was, and pushing his fingers into my spine all over. From the outside, everything was described using words like great and perfect. The only issue was one small on my spine which was very painful when he pressed it. I went for X-rays and returned to the doctor for the bad news.
X-rays reveal hypnosis (minor curve in upper back), scoliosis (lateral S-curve in spine), and spondylosis (degeneration of the spine). Crikey! It's the spondylosis that is most unpleasant and the likely cause of the pain possibly a nerve occasionally trapped by vertebrae that are too close together as a result of disc degeneration. I've been researching information and how to fight back on the internet and I'll be going for an MRI scan soon to find out more about what's going on inside. There are nasty possibilities such as arthritis.
I'd appreciate any feedback on this. I have identified various good sources of information on these conditions, treatments, and exercises, if anyone's interested.