A green mark on my leg looks like a bruise but been there for years and why do my legs hurt alot? help?

okay i have put on weight and my legs are really fatty lol and i am like 3/4 stones over weight i have noticed for quite some time now i have like this green bruise on my leg been there for years now and is tender and slightly ticklish and pain full on touch i asked the doctor if it was a varicose vein it wasn't also i noticed if come one even if some one touches my calf especially (lower leg) feels really tender and painful why?? they always 24/7 feel like i have just worked out that sought of a pain any ideas what it can be? people thanks x