Hi DaisyBee and welcome!!
And exactly what test did your GP claim showed that the PMR was gone? There is no test of any form that can "confirm" that you have PMR or do not have PMR. It is a diagnosis made on the basis of the clinical picture - your symptoms - and possibly a high ESR and/or CRP blood test. In addition, PMR is the only form of rheumatism/arthritis where the symptoms get dramtically better within hours of taking a dose of 15 to 20mg/day of prednisolone. However, both the blood tests can be raised for other reasons and are meaningless on their own. One in six patients with PMR never has a raised blood test at any time and some patients who did have a raised level before prednisolone find it falls to a "normal" level and doesn't go up again even though they have a flare up of the PMR symptoms. In addition, the level taken by the doctors as normal for an ESR is anything up to 35 to 40 - they work it out by taking your age and adding 10 and dividing the answer by 2. So if you are 60, 60+10=70, divided by 2 is 35.
However, on the other UK PMR forum we have had a long discussion about this - and many find they are well at levels in the teens or even much lower but anything above what you could say is their "personal normal" is likely to be accompanied by pain. My usual level is 4 - and it always has been, even when I couldn't move for PMR pain. One 90 year old gentleman is well at something similar - anything above 15 means he is in for a flare and needs more pred.
Beware of yo-yoing your pred dose though - it will, in the long term make it more difficult to reduce. That has been seen in medical studies. The main cause of so-called flares is the pred dose being reduced below the level you need to control your disease and the symptoms. PMR is not the disease, PMR is the latin description of the symptoms: many (poly) painful muscles (myalgia) and the symptoms are due to an underlying autoimmune disease that causes your body to attack itself. This leads to inflammation and swelling and that causes the pain. Taking pred reduces the inflammation and, hence, the pain and stiffness. There are other diseases that appear similar, only PMR responds so very quickly to pred.
You are initially given a dose that is almost bound to be enough to deal with it, 15 or 20mg/day. This relieves, manages the symptoms - IT DOES NOT CURE IT. There is no cure at present, it can only be managed using pred until the underlying disease process burns out - maybe in a 2 to 4 years which is the case for about 50% of patients. About a quarter are able to stop their pred in a year or less - but they are much more likely to have a relapse and have to start all over again from scratch with the pred. The second time round may be nothing like the first time as MrsG has already said. The rest, about a quarter again, need a low dose of pred for a much longer time.
If your symptoms started to come back at 11mg you should have stopped there for a time to see if they would settle. No reduction should really be more than 10% of the dose you are on - so never more than 2.5mg at a time from the outset and preferably less - but 10mg often poses a problem and below that drops of more than 1mg at a time are fraught with difficulty. Below 7.5mg/day a drop should be 1/2mg at a time. But if the symptoms return - the PMR is probably still there whatever the bloods might suggest. And you need a couple of months between drops to allow your body to settle down. You can have similar pain to PMR from dropping the pred dose - pain that starts quickly after the reduction and then improves over a period of a couple of weeks is probably due to steroid withdrawal, pain that starts more slowly and increases is more likely to be PMR escaping from the pred net. When you are going to reduce the pred, make sure you have as little as possible in your diary and plan lots of rest that first week or so - and the reduction will be much more likely to work.
As for the