For me, personally, it's the PAIN ...
2 whole years now of non-stop pain, which is always there in the background, but much worse when lying down in any angle.
I've learned to live with it over this time (very strong painkillers etc work on
some parts for a time, but all these have no effect on this 'new and different' pain I got now. Turns out this latest thing is something that footballers get
Anterior Cruciate Ligament injury (ACL), in my case I'm pretty sure caused by a fall out of bed about a month or so ago. (For the past 2 years I have had to sleep in a rigid position on my left side right at the edge of the mattress, as I cannot lie on my back, and the slightest movement causes searing pain in my lower back). My walking stick is always to hand by side of the bed, as I have big problems getting in and out of bed and need the stick for support - indeed any kind of movement like getting up from a chair, in and out of the car, etc nowadays invariably involves spasms and pain, if even just momentarily.
I fell that time in a very awkward and painful position and had to remain there for some time as wasn't able to reach the walking stick (or mobile phone even, to call for help). That's when this latest pain began - and got worse few days later, the incidence when I heard the 'popping' sound
(ACL above). Life was sheer hell for a few days after that, but it seems I did all the right things at the time - without knowing what it was, so the worst is over (I hope!) for now at least.
Just complicates matters when trying to sleep though.
So, I look for distractions to take from the tiredness and the pain on those occasions ... Thank goodness for the World Wide Web! My saviour (and also lots of other people too ... you'd be surprised the number of people who find themselves in the same boat). Sometimes one of the best 'treatments' is to be able to write about it, let off steam, so to speak, even if no-one else is reading or listening - it helps tremendously.
"A trouble told is a trouble halved". So very true.