jack russell suddenly yelping in pain

by brielle
(nj)

My 4 yr old JRT suddenly started yelping out in pain. It started when we picked him up about 15 min ago. He yelped out in pain. Loudly. He is playing fetch, running and walking with no problem. No limping. He is eating and drinking fine. But in his abdominal region right behind his front legs, he seems yo be in pain. We laid him on his side and examined him...no crying. Yet when he jumps off the couch or moves suddenly he yelps and is in obvious pain. Maybe a pulled muscle? I know the best thing to do is take him yo the vet. That is obviously our next move - however we are waiting for a family member to return with the car so I was hoping someone might have an idea what this is in the meantime. Any ideas will be appreciated. Thanks