See your regular doctor to rule out any underlining cause, if nothing else doc will probably give you a prescription for Sildenafil (generic Viagra). Viagra is expensive and most insurance will only pay a small fraction of the cost, even the generic comes in around $48/pill if you paying out of pocket. My doctor gave me a prescription for 12 generic pills, insurance would only pay for 4 pills . If you are an AmazonPrime member you can have your script filled by their pharmacy comes out like $1/pill and then you don't need to deal with insurance and all of that other bs