Frieds, are you still sleeping on your back? And if so, are you using a pillow beneath your knees? If yes to the first, and no to the second, try the pillow. It will help reduce strain on your back while sleeping.
You're around 8 weeks now, yes? There can be many reasons for the backache...referred pain from all over the place, too much activity too soon, inadequate pain management, wearing old shoes that adapted to your old gait but are now impeding your new gait...among the many.
How long? Get out the crystal ball! It varies a great deal from one individual to another....but FULL healing takes at least a year, and often up to two for all the soft tissue. What helps? Continue to ice, use pain meds effectively, calibrate activity by listening closely to your body, continue to build in plenty of rest time. It is ridiculously easy to strain to the point of causing tendonitis somewhere, and then the pain just keeps cycling around.
But also be aware that stiffness after being at rest for a while is totally normal. If the backache, or pain anywhere else, works itself out after some movement, that is totally normal. If the pain is constant with any activity, then you need to go back to the basics for a few weeks to get it all under control. If that still doesn't help, it may be time to consult your OS.
Does this help?