That bursa over the greater trochanter has been my main issue off and on over the three years since my surgery. I felt it during my first steps down the hospital hallway, and it was the hindering factor during the next month as I tried to get away from the crutches. Somewhere between 5 and 6 weeks, it stopped being a problem, and I thought that it was over. It is fine 90% of the time now, but a few times a year it will flair up; usually when I am switching to different sports at the change of seasons.
I spoke to Dr. Gross about it (he was kind enough to call me at home). He said that it was not uncommon, agreed that it often occurred with an increase or change in activities, and usually got better over time. He also mentioned the cortisone shot if it did not get better in a few weeks. His main suggestion was to do repetitive exercises with minimal resistance, in order to get movement and circulation to the area, without putting a lot of stress on it. This has usually worked well for me, especially in a pool. I have never resorted to the cortisone shot.
The other important thing that I have discovered is the connection between the bursa being irritated, and any tightness in the IT band that runs across it. During the last bursa flair up that I had a couple of months ago, I used a foam roller to release the tension in the IT band, and the bursa got better in about two days.
I have a theory as to why mine was sore right after surgery. According to the surgeons measurements, my leg came out about 4mm (roughly .16") longer after surgery. This is not much, but it effectively makes the IT band slightly short, so it puts more pressure where it runs across the bursa, until the IT band eventually stretches out to accommodate the longer span.
Anyway, I would offer you encouragement from someone who had serious bursa pain and issues for the first five weeks, and after six weeks, has had only occasional flair ups that can be controlled with exercises and rolling the IT band.