Leg Cramps(we think)

Our 6yr old male Basset, Winston, has been doing something strange which started yesterday evening. While I was preparing his dinner, my wife noticed he was holding up his LEFT front leg. We checked his pad for debris, and found nothing. He ate as normal, but later that night pulled up his RIGHT leg yelping!!! After about 1min, he went along as usual. He had two walks yesterday and did fine, and he has no problem getting on/off our porch and in/out of his recliner. This morning, he did the same thing, but this time he alternated between legs at the same time. We are waiting to hear back from our vet(she is very good about returning calls!!!). The only thing we can think of is a reaction to his medicines for his allergies. Last week he started the following:
Cephalexin 250mg every 12hrs
Cephalexin 500mg every 12 hrs
Ketoconazole 200mg 1/2 tablet every 12hrs
Prednisone 20mg 1 1/2 tablets for 5 days
1 tablet for 5 days
1 tablet every other day 5 days
1/2 tablet every other day until
finished.
The reason for the antibiotics is a minor bacterial infection from his allergies under his arms! He had this last year but no leg problems! Any help would be great!
Steve and BettyJo