What causes leg pain, cough and puffy nose while recovering from flu?
Leg aching, in particular the upper legs, does go with influenza. It would be less likely related to the Mirena IUD - pelvic cramping is more likely with the IUD. Sometimes women get some leg aching when there are pelvic symptoms but you are not having bad pelvic symptoms.
Regarding blood clots, I would think it more likely if your symptoms were in one leg rather than both at the same time.
So, although these things are possibilities, I think they are less likely, and the leg aching is probably still attributable to the flu. You aren't over it yet - still having a cough and I'm going to guess a bit of fatigue too.
You should start to feel better in the next several days. However, if you feel it is getting noticeably worse and have any signs of a blood clot then you should go in to be seen promptly.
I hope this helps. I can totally understand why you might feel worried. For now, I think it is just a symptom of the flu.
IT band less likely to be source of a clot than the calf.
You may have strained the IT band. I would expect swelling below the level where a clot would be. Do certain positions give you relief from the aching?
I think for now, just watch and observe and if the problem gets worse then do go in.
You might also find these exercises helpful:
Without being able to examine you, I'll rely on your observation. Observe, and if it gets better, no problem; if the aching gets worse OR doesn't go away, then go in to be seen.
If it is a strain, it might take several days to get better. But it should not get worse. Any signs of it getting worse, then do go in for it to be evaluated. I am being ultra cautious because of your hereditary disorder.