liver resection

I had liver resection surgery and removal of gall bladder in February 2010. I work in an environment where there is heavy lifting involved. I have purposely lifted nothing more than 30 lbs since my surgery, and it is now July (5 months since surgery). A few days ago, I lifted something that I thought would be okay, but ended up this item was probably more than 50 lbs. Since that time, I have a weird feeling around the incision. I need opinions as to what this could be. Muscles that have not been used in months...or possible hernia. Thank you!!!!!