Thank you for the answers.
Ok, so we may be dealing with a bit of nature/time catching up as well. If you are not already doing so 33 is old enough that paying attention to general health and mobility as well as gym time and mat time will pay dividends. There have been a few threads on this here. I am thinking of FightinIrish's 5/3/1 thread and KMCNYC's fantastic mobility thread. I am going to emphasize that you get aquainted with your new life partner, the foam roller.
Damn, you are way tougher than me. I took a drag off a Marlboro Red in college and said nothing I can't hurt back gets to hurt me that fucking bad. Nicotine has been in your system in fairly high doses since mid puberty to now.
Ok, so maybe this is a re-occurence of asthma symptoms now that you are not suppressing them by smoking. Quitting smoking is still worth it.
Ok. Please keep the rescue inhaler handy. It is called "rescue" for a reason. If you have not done so tell your BJJ teacher about your asthma and make him/her aware of what to do if you have a serious attack. Don't be too proud to do so. It is just part of the game.
Keep up with your Doc and with the specialist. I hope that works out with you.
I am going to give some suggestions in three areas.
First, general health/every day stuff. If you are not already start some breathing exercises. Learn to breath with the diaphragm. Basically, you want everything south of the sternum to expand on inhalation, not just your belly. So sides/obliques and the lower/floating ribs in the back. Usually laying in a fetal position makes this easier to feel/facilitate at first. If you are not doing something like this already I can dig up something. If you are already doing some kind of Yoga/Zen breathing work keep at it. Breathing patterns seem to have a great deal of effect on general health and joint/spine stability so they are worth training.
Second, cool-guy gym stuff. Your heart-rate is low enough that you can probably just jump into anaerobic conditioning. Just please be careful, keep your rescue at hand, and clear it with your Doc. I guess Prowler pushes are the rage now, but I have no first hand knowledge of these. I do like and can vouch for kettlebell swings/cleans/snatches, squat thrusts, and sledgehammer work on a tire. Other people can probably give you better specific advice here. Cardio is my weakness and I do not have a medical excuse other than severe chronic LOFT(Lack Of Fucking Talent). Barbell complexes are supposed to be good and not have a bad effect on strength, but I never really gave them enough of a shot to recommend them over the above.
Third, on the mat stuff. While you are working on bringing your wind up you are being forced into a position of having to get maximum returns on your energy. This is not a bad thing. It is why martial arts/BJJ is worth learning. So, while sparring try to make the other guy work twice as hard to get half as much. Make him push into structure or nothing. Make his diaphragm carry your weight. I am sure you know all of this but you will be getting object lessons in its importance everytime you step on the mat.
I don't know what your style of grappling is, but even if you are a high energy/pressure guy take a month or two to work on flowing and letting efficient mechanics do the work. The time to do this is when you are fresh, then "prove" the technique to yourself when you are exhausted. If you foster good technique it will always be there for you. You will never fight alone because Issac Newton, Archimedes, and the rest of the God's of Physics will be willing to help pull a train on anyone you face. To this end I suggest purchasing copies of Saulo Ribeio's Jiu Jitsu University(Book) and Roy Harris's Jiu-Jitsu Over 40(DVD). Both do admirable jobs of showing survival positions/strategies and ways to manage opponents who possess multiple physical advantages.
Hope this is of some use.