sorry I cannot comment as not in your situation but hope someone can help. TRY to continue with that positivity, it is hard when more sh*t gets thrown at you. Fingers crossed
I finished chemo radiation in March 2012 and from then had hip pain just like u are describing... it has eased a bit through time but every now and then it "locks" should I try and sit a certain way or stand too long. They sent me for bone scan at my last review but it was all clear... they will only be looking for the c word in that scan not bone density so that's maybe another possibility... I suffered slot of side effects including nerve damage in my hip legs feet and hands from my treatment but thru time of adjusted and know my limits... you are right to get it checked out but more than likely it's a side effect of your treatment... I know it's so hard esp when a new pain comes along and you think the monster has returned but you are being checked and reviewed thoroughly so (and I know this is hard) try and take comfort they are keeping a good watch over you...
what you describe is what I used to get as well and I still get some pain/discomfort in my hips and groin especially after traveling. I remember, just like you,
in the first year I used to worry it was something sinister but at each check-up I would be reassured that everything was good.
My chemo-radiation finished in early May 2010 and I felt pretty good until the end of August when I started getting horrible hip pain shooting down into my leg, plus severe vaginal pain and revolting discharge. My docs feared the worst and were trying to persuade me to agree to a partial or full exenteration and I was on some really serious painkillers. It all turned out to be simply necrosis caused by my treatment (which disappeared) and some sort of inflamed nerve, which also sorted itself out.
I must admit that - three years on - I tend to panic at every little twinge "below the belt". I agree with Naz that keeping active helps.