The flashing “D” indicator on your dashboard indicates that there an electronic problem with the transmission’s electronic controls. Failure to rectify an electronic problem promptly can easily lead to much more expensive mechanical repairs to the transmission.
Unfortunately, since you have been observing this trouble sign for about 4 months, I think that you have crossed the boundary from “promptly” taking care of the problem into the category of ignoring it in the hope that it would cure itself.
I strongly suggest that you NOT take the car to AAMCO unless you want to be told that you need a new or rebuilt transmission–whether you really do or not. The chain transmission operations (AAMCO, Lee Myles, Cottman, Mr. Transmission) are known for giving the most dire diagnoses, charging the most, and delivering poor workmanship.
You should take the car to an independent trans shop that has been in business for at least 3 years. Ask friends, neighbors, relatives, and co-workers for referrals to an indy trans shop in your area. In addition to being cheaper and more competent/more honest than a chain trans shop, the indy shop will likely also be cheaper than the Honda dealer.
You should also begin to read your Owner’s Manual. If you had, you would have seen essentially the same information that I posted in the first paragraph. Repairs that are done promptly are invariably cheaper than repairs that are deferred, and it is likely that you would not have deferred this matter if you had read the information in the manual.