What Causes Pain In Left Groin Area?

I am having pain in my left side groin area. Yesterday was working in my yard (pretty heavy duty but no heavy lifting was involved). later in the evening had sensation that I was urinating down my left leg(but wasn t) This morning upon waking, had Sevier pain in my groin area into left hip. Ice packed ,and applied heat to area but have had no relief. I took 5mg of Percocet that I had left over from low back surgery done on march 2015 . still no relief. I also am on blood thinner, from clots on both lungs.2010. I do not feel any lump in my groin, but am wondering this could be a hernia.