There is most likely more than one area that needs attention.
You are a system of systems.
Yes, your psoas is probably an impacting factor.
Jill Miller Smashes Your Guts! (and psoas, and tacked down viscera, and matted down abdominals…) Part 2
Episode 301: Psoas Flossing and Biker Hips
Episode 290 Haiku Contest And Landing Position Part 1
Episode 290 Haiku Contest And Landing Position Part 2
Episode 129: The Twin Bowstrings, the Psoas and Scalenes
Episode 87: Hip Impingement 2: Band Variation
Episode 75: Your Inside Psoas Bits, World Record?
Episode 40: USAW Oly Prep: Some New Hip Love /Psoas/Calves
Episode 26: Hips and Seppuku: Psoas and Hip Soft Tissue Mob

You have missing range in your posterior chain.
Stretching and foam rolling is a first step. If you are not hitting the areas that are tight or restricted then these areas will not improve. You need to freestyle and hunt to find what needs work.
What you do prior to a workout would change based on what you are doing that day, your tight areas, and places of restriction that you have.

Good to hear you are seeing improvements with what you are working with.
Working with the area with the most restriction first will open up other areas within the system.

As Kelly has said in some of the videos and on the Joe Rogan podcast, tissue failure is rarely the result of a catastrophic event, but rather the sum total result of billions of repetitions over a period of time.  Meaning, that you are not moving correctly, or good enough to avoid that tissue fault.  But that is still not the right perspective to have.  When I started having back pain in that area I adapted that mindset into everything, meaning everything I do day to day is contributing to the tissue injury, from how I walk, run, work and so on.  Am I walking with right form using the right shoes…  Am I sitting to much at the office.  Is my spine in proper alignment all the time.  When you couple this with the tunnel approach(impossible to recover from bad form under load when you start out with bad form) you can start making a bunch of little tweaks here and there and then back problems and other issues go away.  The things I have found invaluable in my journey is a foam roller, lacross balls, a car orbital polisher, voodoo wraps, and a good chiropracter willing to actually talk and work with me though my dysfunctions. 

Identifying what needs work isn’t a bad thing.
Getting some of these things in order can help your bigger issues come around as well.
Have you watched the videos that address sitting to improve your position when sitting and different things you can do when you must sit for extended amounts of time?
You don’t need to hit all of your areas that need work everyday.
Instead pick the first 2-3 areas will lead to the most improvement and attack those first.
You want to spend quality time vs quantity of time.

Your original question about pain from the crest of the hip is a tell-tale for having a locked up sacroiliac joint, in conjunction with a l3-l5 issue in conjunction with the hips locked in extension.  This can lead to very serious problems.  I know because I suffered the exact same thing.  The pain while sitting is basically an elevation of the same condition, meaning its getting worse.  High level athletes are able to perform with similiar or worse conditions because they do so many things.  You are in good shape, and doing a lot of right things, so you are able to be functional in this condition, but as you grow older it will catch up with you. You have to find a good chiropractor that will work with you to unlock the sacroiliac joint and l3-5 out, you cannot do that on your own.  A very good massage therapist may be able to unlock them but that is rare.  When you have that level of fault the muscles will not relax via stretching, its part of the protection mechanism.  They have to be massaged lose.  Once your back is straightened, and your hips and sacroiliac is unlocked you can begin to work on a few areas.  The first is the hip flexors.  they need to be stretched and lacrossed, to do that get 4 balls and tape them in a pyramid structure.  the second area is the psoas.  the third is with hip mobility, put a foot up on a counter and try to get that foots knee outside the shoulder.  As to your calfs being sore, I suggest listening to the joe rogan experience episode with Kelly, the walking/running part will give you insight as to the problems cause.

Debating on whether or not to do something isn’t a good place to be. You need to have confidence and commit to it or not commit to it.
High standards are definitely a good thing. Have it work for you.
If one area doesn’t stick out just pick one of them.

Sounds like your calf is also tight. Go to work on them.