Easiest Thing I would say is to find an electronics tech who knows what he's doing. as long as he knows how to use his equipment, finding the bad joint shouldn't be a problem. Just do a continuity test on each joint around the chip to the bottom of the PCB till you find the cold or broken joint, then de-solder, and re-solder. NEVER just re-flow the joint. That's one of the worst things you can do. A cold joint is usually oxidized and has air bubbles in it so re-flowing it could just oxidize the whole joint and cause it to be non-conductive. Plus just reflowing the joint evaporates some of the solder which will take down the conduction and possibly not fix it in the first place Typically a problem is the soldering process didn't get enough solder in the first place to the joint, or the solder didn't get enough heat applied to it.
