About three weeks ago, we took our bichon-poodle mix dog to the beach. He loved it. Afterwards, he developed a slight limp on his back right leg. He runs fine, does his little bichon buzz daily. just sometimes, as he walks outside, he gets that hitch in his gait and limps for a bit. he shows no signs of pain and often stands on his hind legs as he begs for my food. but it has been three plus weeks now and he still has that hitch. should i be more than just a little concerned?