I do not want to worry you, but my Blondie did the same thing for 3 years until she got diagnosed. She yelped when picked up (not always but lets say once out of 3 time) and it was absolutely the only symptom.
The vet noticed it one day, when I went in for a vaciine, and mentioned SM. (props to that vet, who just graduated vet school!!!) I read up on it and thought "she doesnt have any of the symptoms" so I kinda ignored it :bang: but I did remember the symptoms as I watched video's of dogs with SM.
And 2 years later.. the dreaded "other" symptoms started to show.
I cried for two straight days as I knew in my heart what the truth was, joined this forum (thank god) and scheduled an MRI immediately.
Now, as so wisely said in the post before, it could very well be something else. (maybe another back problem or a muscle problem..) so no need to panick.
But if she yelps, something bothers her.
Also, if it is due to SM, it doesn't mean other symptoms will necessarily pop up, or that it will progress. But as it is very, very common, I would defintely read up on SM and keep an eye out for any symptoms.
Also, as Margaret said, please do get insurance coverage! I only wish I had thought of it... Now when the time comes for BLondie to have her surgery, I will be paying off my credit card for a very long time.... I got insurance AFTER the fact! ( with all the costs for SM adding up, I can't imagine what I would do with a large emergency vet bill or cancer treatment or xtra surgery etc down the road )