Hip flexor strain or something else? Please help!

Hello I am in dire need of some help. I had an injury in mid July of this year playing handball by making a sudden movement with my left leg and I guess I landed wrong. I had an extremely sharp pain in my thigh/hip and could barely walk the rest of the day. There was no bruising and it gradually got better throughout the week, and after a week I started my sports and exercise. After a while it began to hurt much more so I took another break. It felt better so I started cycling again and then afterward It started hurting and noticed a crunching popping sound. Not like one single pop, but like if something is grinding with something else and that only happens in my left hip and not my right. This only happens when I stretch my thigh sideways, like in a crane position. It's not very painful, but it is uncomfortable. I went to a PA about 1 1/2 months in through the injury and he said to just rest it. I then went to a Orthopedist in Tijuana about a month ago and he said to just rest it and gave me some anti inflammatory drugs. Can a Doctor please help me? I am a very active individual, and I don't want to go running and cycling right now for fear of this becoming any worse and I am planning to run the LA marathon in March of next year so I need to figure this out.
My current condition: There really is no pain, but I do feel discomfort. It feels tight, and it just feels different from my other hip/leg. When I walk or stand for a long period, it begins to ache, not very painful, but like a dull chronic ache, and it also does that after sex. The crunching/popping that I mentioned at the hip/thigh when I stretch a certain position worries me the most.
If this is a hip flexor strain, what should I do? should I rest it longer(if yes, how long) or start strengthening it?
Is this a chronic pain that I will always have? or do I need surgery?
Thank you so much if you can help me!

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I forgot to mention when I stand or walk for a long period of time as well, the rest of my leg begins to ache, as well as my knee. The knee pain wasn't there in the past but it began to hurt recently.

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I went to the clinic again, and the doc told me that my x-rays came back fine today.