A New Affliction?

I seem to have had a sore thumb recently.  And it has been happening fairly often. 
I was blaming it on the weight of the Leftover Pi shawl while working on that.  But now I think it is perhaps something else.
I notice it hurting while texting.  Not that I text that often, but I have been blogging everyday, mostly on my phone.  I read Facebook and I follow a lot of blogs on Google Reader on my phone. I notice that using my phone in my right hand has been a bother. (I am a leftie.). And probably my iPad hasn't helped things.
Is,there such a thing as Texting Thumb?