sudden onset of all over body pain

Question
My 3 yr old black lab today was run up our stairs and started yelping in pain, through out the day he would yelp here and there, just laying down he would yelp or he wouldn't walking up the stairs he would yelp or he wouldn't...My vet who I am not happy with anyway, didn't really have an answer and said it was probably muscle spasms and gave him prednisone and robaxin,She said to bring him back on Saturday if he was not better...I have since found a new vet and am thinking of bringing him there on Friday if he isn't better. What do you think I should do and do you think the diagnosis is correct?

Answer
A second opinion can only hurt your pocket book.  It is very difficult for a lay person to judge a vet.  

Different things cause such problems.  A friend almost lost a highly valuable dog to Lyme disease because it was initially treated for a sprain.