MSK related back pain triggered by virus?

[Lunaballoon]

I've had several bouts of musculoskeletal lower back pain with referred pain down my outer calf. The last bout lasted about 18 months after which I was pretty much back to normal for about 6 months.
I came down with Covid after returning from holiday and lo and behold the back/leg pain is also back.
I don't know what triggers these back pain episodes (I hadn't done any awkward lifting or anything) but I'm wondering could it have been Covid? Thinking back, I think one of my previous bouts may also have occurred after Covid/bad cold.
Has anyone else experienced this?

I find with a bad virus all the bits of me that sometimes ache/twinge eg my lower back, start hurting. Sometimes it's the first sign I'm going down with something in fact

When I had chickenpox (as an adult) my back hurt so bad I could hardly walk, I was moving like a crab.

I haven’t had Covid/flu vaccines since we had to during the pandemic. I must keep on top of them now because for me this physical inflammatory reaction is far worse than the more obvious symptoms of the virus.

Probably a bit of a long shot and I don't want to be an armchair doctor but have you ever had psoriasis/iritis/any other symptoms of inflammatory arthritis? Is the back pain worse in the morning/better with rest or better with movement?

I've got Axial Spondyloarthritis which is basically arthritis in the spine - I got diagnosed via MRI. Generally well managed but viruses leave me with terrible back pain and aching joints. Nass website has a few questions that can let you know if it's something that's worth exploring further.

Did you spend any time in bed while ill ?

I was convinced during a previous episode that I had some form of inflammatory arthritis but blood tests came back negative and an MRI scan showed minor disc and facet degeneration consistent with my age and no nerve root compression. My GP assured me it would sort itself out in 10-12months. It was more like 18 months but I’d been more or less pain free all summer until I got Covid.

Only one day during the early stages when I felt very rough. I was mostly up and about, just taking things easy.

I just wondered if you’d changed your physical movement especially with already potentially dodgy back it’s irritated it ? I ve had similar issues not virus related but have had to be SO consistent with maintaining strength and doing mobility work boringly regularly otherwise everything flares again …

I admit when the pain had subsided over the summer and I was “back to normal” I did ease up on the exercises that I was previously regularly doing. I still swim at least once a week which I think helps.
I must reintroduce the core exercises which have also been very helpful.

Have you seen a physio?

Low back pain that's referred down the calf could be sacroiliac joint syndrome, or it would be weakness in your foot causing imbalances when you walk.

If I start to get pain/discomfort I use https://www.physiocheck.co.uk/ first and read up on the exercises once I have an idea of what might be causing it.

I strongly suspected SI joint syndrome during a previous flare-up. The location of the centre of pain seems to correspond exactly to the SI joint but again MRI showed no particular issues there.