Just diagnosed with asymmetrical breast tissue. mammogram looked different from last year, breast is painful, should i be worried? what can it be.?

Asym breast tissue: could be nothing but a change in mammogram warrants further testing - either a biopsy or additional imaging such as an MRI or 3D mammogram. In my opinion ANY abnormal breast issue needs to be investigated even if it is something as simple as more frequent mammograms . I would discuss this with your doctor - you could always get an opinion of a breast surgeon.

Normal: Asymmetrical changes in breast tissue are common. the pain is due to ductal dilatation from hormones causing ducts to partially close off and accumulate fluid. Path on mammo that might be of concern is microcalcification or a stellate lesion. Asymmetrical changes if at all suspiciaous can be resolved with an MRI of the breast.

Breast asymmetry: Breast asymmetry is common. If it is very different from previous then a repeat in 6 month if nothing else is found. If your breast is painful then have your doctor check them. Breast congestion can cause pain. Hot compresses can help open up the ducts and relieve the congestion. An exam by your doctor will clarify what may be doing on.