Next time your at the gym, start doing lots of side bends, side twists, and sit ups, but you are on a
long road as its the hardest place to
lose weight, 2 of the best things you can do is walking and swimming, and try walking with a weighted back pack, start low and build it up to around 20 kilos, and as for your chin it should also slowly go.
Remeber its an all round thing losing weight.