How can blood tests determine arthritis unless it's rheumatoid? I would ask for an X-ray to determine the amount of normal wear and tear in the joints so that I could manage any aches and pains with over the counter medication.
Glad that those tests have shown what you are low in and there are remedies for that.
As oestrogen levels drop muscles may become lax = aches and pains. Also the body may become dry: inside and out; scalp, skin, vagina, deep in the ears, eyes etc..

Without stopping your HRT you probably can't know if you are through into menopause. Replacement may give a false impression of where your body actually might be.
Peri - those years where we notice changes in mood, periods, skin condition etc. continue until the last monthly period = menopause. We are told to count for at least 12-14 months without a bleed of any type B4 we can believe that we are 'there'

. So for any medic to suggest that you are into menopause whilst U R using replacement therapy is a bit far off the mark.
Some ladies go into peri from early 30s, others don't reach menopause until mid-late 50s though this is not usual. Medics get stuck on numbers

!
MayB keep a mood/food/symptom diary to chart progress? Sunshine is also good for topping up VitD levels - as is brisk exercise [note to self

- does gardening count?]
Let us know how you get on? Who is prescribing the testosterone and in which form?