macsambo,
Kyphosis just refers to the curvature of the spine, looked at from the side.
Normally, you have lordotic curves in the cervical (neck) and lumbar (lower back) spine regions, and a kyphotic curve in the thoracic (chest) region.
Thus, a kyphotic curve is concave to the front (apex to the back) and the lordotic curve is opposite; it is concave to the back (apex to the front).
So, if your normal lumbar lordotic curve has gone past straight to being kyphotic, you probably need that fixed. That could change all of your spinal biomechanics and even put pressure on the cauda equina (the terminal nerve roots).
Now, some surgeons will say that a curve is becoming kyphotic, when the normal curve is straightening out, but has not gone all the way to actually being a kyphotic curve yet. So, you may still have a lordotic curve in the lumbar region, but it is straighter than normal. This is sometimes called a "flat back syndrome" after spine fusions.
These can cause pain, again, because of the change in the biomechanics. Which is why many of the spinal instrumentation system used for long fusions changed a few years ago, to make sure that the proper sagittal curves are maintained.
Sometimes, if it is a flat back syndrome, the fusion has to be redone, but, as you probably know, that is a big operation.
If this is hampering your ability to lead a productive and enjoyable life, keep looking for a solution.
Good luck. Hope you find what you need.