Newbie Medical Insurance Questions - California- Primary Care, Specialists, Etc

Hey All.. So I have never had insurance until now or will once the card etc, arrives.

Im in SoCal and I have IEHP. I have some questions, hopefully anyone can offer some insight.

If I dont like the primary care Dr Im given, can it be changed? Or am I stuck there? I live in a small town and the pickens are slim, but the larger cities with more choices arent that far… Can I request it be changed, and choose my own thats under IEHP?

I have been having stomach issues for awhile, and want to get it checked out by a gastroenterologist. If I go to my primary care Dr… can they say, oh let me just give you some type of medication first, or bandaid and wait to see, intead of giving me a referral to see a specialist? Can they deny you specialist care? I thought all I had to do was find a specialist on my own that accepts my insurance, that I felt I needed to see, and then contact insurance, etc. But it seems every special care has to go through a primary care Dr.

If primary Dr does give referral for any type of specialist care, is it to only one specific person? Or do I get to choose from a list of some sort of Dr’s under my IEHP plan? I would like to be able to look up, and research on my own, read reviews, to decide who I would be comfortable seeing as opposed to, nope this is who primary care Dr told me to go to…

If I do go to a specialist, does the primary Dr control what THEY think I need to get done with the specialist, what tests, etc, and thats all that wil be done based on primary Drs recommendation? Or does the specialist get to decide, etc?