A diet will fix the chest fat. Eat a healthy, balanced diet, so: vegetables, grain(but not white flour!), fruit, lots of water(this really helps, my best advice is to drink a glass of water as soon as you urinate. This will make you use the restroom a lot for a few days but after that it'll normalize and you'll simply be drinking a lot of water - that makes the hormone receptors stick further out of your cells' lipid bilayer so they're more receptive), and meat, milk and eggs, but those three in moderation.
Dissymmetry with the pectoralis muscles is really common. Actually, I'm sure it's common on all muscles, but the pectoralis are very close together so it's visible. In any case, there's nothing you can do about it. But you still have a layer of fat over them, so who knows, maybe they're actually quite symmetric.
Walking and jogging is great. If you aren't doing any other exercising, I'd suggest some bodyweight exercises: pushup, chinup, australian pushups (reverse pushups), planks, wall sits.
Also, jump rope is great.