What could be the cause of swelling above my left hip. about a year ago i had surgery due to herniated discs on my left side? could that be a factor?

Varies: There are many potential causes and a good exam can go a long way in determining the cause. Having a disc surgery would usually not cause swelling above the hip. Some patients can get a bursitis and this can cause pain, swelling, and tenderness above the hip and there are some good options for that if that is the case. Consider being seen.