After a checkup the doctor thinks its just the muscle. The joint 'behaved' so I have some anti-inflammatory cream to apply. That may solve it, but it may not. I'm unsure of it just being the muscle as I've had worse pulls than that which have sorted themselves out within a few days.
I'll persevere and hope that this stuff works. The doctor was going to prescribe me some co-codomal but decided not to after I mentioned the mess it made of me last year. I'd rather chop my arm off than go through that again.
Only one problem at work over the two days I wasn't there (that I know of). One of the projecters didn't work. I set it up and it worked perfectly - I suspect that the highly qualificed academic hadn't turned the mains power on. The laptop would have worked on battery - people never tend to check the simple stuff, do they?