Thanks for all the suggestions guys!
I used to have an ergonomic keyboard and mouse pad but typically these disappeared in one of the moves I made (what is it with that?! I swear whenever I move house a random selection of stuff disappears into some black hole) I think I should definitely invest in that again, for now I think the splint should do the job when I'm writing and typing, as for texting maybe I should just revert to the good old fashioned phone call instead! lol.
I've had Flagyl once a few years ago and other than that the only antibiotics I have is the occasional erythromycin for throat infections so I don't think its caused by something like that.
I've done a fair amount of googling and it seems the best thing to do is rest and heat and if that doesn't help to get a steroid injection but as far as I know only a rheumy would be qualified to administer that so I think it might be worth me getting a referral just in case its still bothering in a couple of months.
Thankyou for the quick and helpful responses people