Why did I wait for it ?

.. to become unbearable.
Quick summary of the psoas tendinitis or tenderness symptoms:

"Pain will generally be experienced for a short period of time during vigorous activities like jogging or kicking a ball with your instep, as well as more passive activities such as getting up from a seated position, extending your leg while driving, walking up stairs, lifting something heavy or bringing your knee up to your chest (especially against resistance). You will often find it difficult to lie down comfortably without support. Occasionally pain diminishes while in use, but it returns with a vengeance when you stop your activity. Average time from initial onset of symptoms to diagnosis ranges generally between 32 and 41 months."

Not related. Just made me laugh. Karate Kid on  a surfboard. Sorry.

Key point:  "diagnosis ranges generally between 32 and 41 months."

What? 3 or 4 years ?

I guess I got tricked, but I waited around 5 years myself.

As they say, it goes and goes away. Someday you can walk, someday you cannot.

Sometimes you can run, sometimes you cannot. You get used to the pain. The pain disappear when you are warm, usually. You change shoes. Use other muscles. Stop exercising (because it is boring). And rest (without thinking about it). Then it goes away for longer.

But eventually, it will come back. Because you are still sitting in front of this f** computer, eight hours a day (if you are lucky, usually it is waaaayyy more).

Now you know the symptoms. Do not forget if you have back pain, as it is related. Go to the doctor or physical therapist. Just for a check-up. In doubt, do Yoga or stretch:  You cannot really hurt yourself doing this. You can only hurt your feelings by seeing yourself not being able to last 2 minutes on the plank. (one minute and 15s , exactly). Or not being able to do 50 abs (20, to be precise). Or not looking like them.

Ridiculous , isn't it ?

Make you a favor. Listen to your body.
Not to your Ipod. Or both.