Here in the good ol' US of A, you can see any doc you want, as long as you can pay for it. If you want insurance to help defer the cost, then you need to comply with the terms of your insurance policy, which can range from seeing anybody you want to having to go to a specific primary care physician and getting referred only to docs within their little network. My relatively low-cost policy is like the latter. If I decide I want to see a specialist, I have to see my PCP and get her to agree. She always does, but it has been an inconvenience at times, mainly with acute issues.