My 1 year old beagle was neutered a few weeks ago and a few days after he developed a large, walnut-sized lump on either side of his penis. He was extremely sore and couldn't walk well and when I took him back to the vet they said it was a type of groin pull. Has anyone ever had this problem? All I could do was give him an anti-inflammatory and morphine. He is fine now but the first few days were brutal.