I get it too, it all depends on the strength of your pulse and your BF%. A bloke who doesn't work out (so they have a weak heart) and has a BF% of 40%+ will almost certainly not be able to see their pulse in their chest, even under heavy exertion.
Unless you're getting other symptoms like light headedness, headaches, nausea, chest pains, etc, under physical exertion or exercising, then you should have no probs. If its really concerning you though, have a chat with your doctor.