Thank you everyone :-)
Yes it's not the best. Worst thing is I need my hands for my job. I've been trying to get away will bending at the elbows instead of raising my arms at the shoulder as thats the bit that feels the worst.
PollyP - the sensation of having carried heavy shopping around is exactly what it feels like. Apart from I can't rermember having done anything like that to have made my arms feels like this.
Toddlers round the legs doesn't sound too great either. Kind of sounds like trying to walk through quicksand... not pleasant.
Hope the sensation passes soon.
Can't wait to get home - and maybe try putting a hot water bottle on them or lying in a bath if that doesn't make the other symptoms to worse.