It will most likely be considered a pre-existing condition, whether or not you received a diagnosis from a medical professional. Most questions don't just ask if you've been diagnosed, but ask if you received symptoms, diagnosis and/or treatment. “Symptoms” is the key word here.

I would suggest reading the definition of a pre-existing condition in your policy information.

As a technicality, most insurance companies are looking for pre-existing conditions at the time of application. Not between the time of application and the effective date. People sometimes apply 1 ½ months in advance. Anything can happen in that time. If you come down with a condition after an application, how can you help that?

What will look most suspicious is that you didn’t have coverage and then as soon as you got it, you started submitting claims for your back.

Also, a health insurance plan is always contestable. Basically, what this means is if the insurance company were to find out there was a non-disclosed pre-x, they have the right to rescind the policy and send you a refund check for the premium amount.

On another note, it’s your health! Get treatment as soon as possible to prevent things from getting worse.

As a technicality, most insurance companies are looking for pre-existing conditions at the time of application. Not between the time of application and the effective date. If you come down with a condition after an application, how can you help that? People sometimes apply 1 ½ months in advance. Anything can happen in that time.