I have a 2yr old Golden Ret. He started limping on his front left side Thursday afternoon and Friday mornign and is still doing it tonight when I got back from hunting.I have checked his paw 2 or three times and can't find anything. There doesn't seem to be any swelling anywhere and he doesn't act like anything is hurting him when I run up and down his leg. He only limps when he is walking. He runs, jumps, chases, retrieveslike nothing is wrong. He even loaded in my boat on the trailer tonight and jumped out on the side where the sidewalk drops off in my yard which is probably 4ft.(may be oneof the problems)

Any suggestions on what it might be? Something I can check that maybe I missed? How would I be able to tell if it was arthritic w/o a $100 trip to the vet?
THANKS