I haven't had pins & needles on my tongue, but I have had weird sensory things there (like fizzy drinks being fizzy at the back of my tongue but flat at the front).
Sensations in the front two thirds and the back third of the tongue are controlled by two different branches of the trigeminal nerve. Depending on where your pins & needles are, you could work out what nerve's playing up. Not sure what good that'll do you mind you!
It is possible to have a tingling tongue because of allergies, reactions to meds, vitamin imbalances and other things too though. Definitely a good idea to get it checked out, just in case it isn't your MS playing tricks on you. That's especially true if your pins & needles don't adhere to the front two thirds / back third thing.
As far as pins & needles on hands goes, I've had them there as well as pretty much everywhere else. Pregabalin has been brilliant for keeping that kind of thing under control.
I'm sure I've read on here that it's possible to have a UTI even when the test comes back negative. I've no idea how true that is, but perhaps it's worth asking your GP or MS nurse about?
I hope it doesn't last too long. Pins & needles on your tongue must be very distracting, never mind painful!