It was about a month ago I started the same type of coughing spasm-the doc said it is all from lower oxygen-just being short of breath. I also think it is allergy/asthma related for me at least. These spasms really get to me though-for me they are definately preg related bc I never have anything like them. The doc said they'd go away as soon as the baby was out.
As long as you are sure thats what you have and there is no infection brewing, I wouldn't worry. If you have a broken/sprained rib, there's nothing they can do for it anyway. Ice it every night maybe? See what the chiro has to say-he can feel it and tell if you have had an injury.
I think its a little early for you to be getting baby's limbs lodged in your rib like that. I don't think that the really painful kicks come for a few more weeks-I've only heard of that from like 34 weeks on.
But of you have David Beckham in there-I guess it could be that!