Reconsider your interest unless you have some serious cheddar to blow. I'm going to explain why. This explanation is assuming that you do not hold any certification what so ever in scuba diving.
The initial cost just to get your open water certification is prohibitive. You have to pay for the course, equipment rental, and travel to and from dive sites including the dive. To give you an idea I lived off the coast and the cost of getting the intro open water certification was well in excess of $2500 USD.
Then you have to obtain the next certification which is advanced open water. This allows you to exceed your dive depth and requires that you specialize in two areas of your choosing. This could be nitrox, underwater navigation, cave diving, whatever. So you pay for the cost of the course plus your equipment rental and your dives. Expect to drop another thousand.
Are you CPR certified by the American Heart Association? You better be. That costs money too. You need that certification to get your rescue diving certification. More money on training, equipment rental, dives, etc.
Then after all that you need to log a number of dives to be eligible to hold an instructors certification. That is even more money invested. I am just estimating but expect to invest over 10 k total to even be eligible for that instructor certification. That also counts the time you need to put in to do all of these dives.
Lastly, I ask you this. Have you even gotten on indeed or other job sites and seen if just having the instructor level certification makes you eligible for a job? Or is it more likely that you need to log the minimum of something like 100 dives and be a dive master and not just an instructor? Keep in mind that part of an instructor's job is sales so there is a commission aspect to the way they make their cash. Don't be blinded by the promise of exotic locals and a decent living. That's how people get suckered into the military.
Lastly, as to your physical problems, I wouldn't worry about it. They really only DQ people from diving who have seizures or other such head problems that would leave them a danger to themselves and others while diving.