What disability insurance would be the best fit for someone like me who has a pre-existing condition?

What would be the best disability insurance plan for me? I am 31 yo, male, single, and am overall healthy except for chronic migraines. I have a feeling my chronic migraine would be a possible reason for me to someday not be able to work and am trying to comb through the policies that would be the best fit. 

*Typically disability insurance plans will cover you for an ailment like chronic migraine if it is only a "condition" when you sign up for the plan. If that same condition later after enrollment becomes a disability then it may or may not be coverable.

**I was looking into long term care insurance instead of disability insurance and realized long term care insurance is more for people who need help with things like bathing or brushing their teeth. I can do all these things but I just sometimes cannot work. I'm hopeful I find a cure for my migraines to never have to worry about this but want to prepare for the worst possible scenario.