Hi Annie DC
I appreciate the research and pain that you have undergone gathering information regarding your problem. Could you answer the following questions please?
1) What is the exact "site" or "location" of pain if you were to refer to a body chart? (please mention current and past episodes)
2) It is not clear from your post, for how long have you had this pain? How many episodes have you experienced and How many days or weeks old is the current episode?
3) Does posture have any relation with your pain? (Does sitting or standing slouched or erect change your leg pain in any way?)
4) Have you ever experienced any low back pain?
5) Is your pain intermittent?
6) What could worsen your pain? Since you have said walking, does the distance or time matter?
7) What effect does bending forwards from your back with your knees straight have on your pain?
8) Is there only pain or is it accompanied by any other sensation such as tingling or numbness?
Please answer these q's so that we can get a clear picture to if your pain is mechanical and can be changed using repeated movement testing. If that works, you may not require surgical intervention.
As for your question regarding compartment syndrome, It can be exercise specific but in your case vigorous walking and cycling are both eccentric activities and one causes symptoms and the other doesn't. That needs to be investigated a bit. Also, could you provide or share some information which has led you to believe you are suffering from compartment syndrome?
Regards
Prachi