Hi Donna R
If the aching is limited to breastbone & arm area (is it upper arms/shoulders?) I wonder whether declining collagen from the low oestrogen means that the weight of your implants could be implicated? Collagen helps to strengthen tissue, so that as it declines with age you may find you have less natural support for the implants.
If you've not had them checked recently I would try to see a plastic or breast surgeon, as you will know implants tend not to last a lifetime & may need replacing after a decade or so if they degrade. If your aching continues after other menopause symptoms have resolved, the surgeon should also be able to advise how best to tackle the problem if the implants are to blame, whether or not they have reached the end of their lifespan.