As I am not licensed in your state, I cannot offer you specific legal advice as to Indiana state law. However, generally, it is a big mistake to give the adverse insurance carrier access to your medical records. They will use that release to check on your records as far back as when you were born, if they want to do so. They will look for any notation in your prior medical records that looks in any way similar to your current complaints ( i.e. headaches, a back complaint, a neck cramp, etc.) they will then try to claim that you had all these problems before the accident and their insured didn't cause anything new.
Remember, the adverse insurance carrier is not your friend nor your good neighbor. The sole goal of an insurance company is to pay you nothing on your claim or as little as possible. You should seek the assistance of a personal injury attorney to guide you in dealing with the adverse insurance company. You also may find it helpful to review some of the Legal Guides I have published on Avvo.com, many of which deal with the situations you are now facing following your accident.
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