The Affordable Care Act eliminated pre-existing conditions starting 2014. Insurance companies are no longer able to deny coverage, charge more, impose waiting periods, or deny treatment for anyone with pre-existing conditions. The only exceptions are procedures like cosmetic surgery that aren't considered medically necessary.
The only medical question an insurance company asks that may affect your rates is your tobacco use. If you have used tobacco 4 or more days a week for the past 6 months, an insurance company is allowed to charge you 50% more than a non-tobacco user.
Preexisting Condition Exceptions under the ACA
Grandfathered plans and short term health insurance can still place limitations on preexisting conditions.
Grandfathered plans are plans that were purchased before March 23, 2010. You can longer purchase grandfathered plans, but you are individuals are able to keep them as long as they would like.
These plans have a grandfathered status and don’t have to follow ObamaCare’s rules and regulations or offer the same benefits, rights and protections as new plans. This means that on many old plans you can still be dropped form coverage for reasons other than fraud, be denied treatment for preexisting conditions, face annual and lifetime dollar limits and more. This means they can either not cover costs related to preexisting conditions or deny coverage all together for preexisting conditions.