I had a mammogram and I was diagnosed with bilateral gynecomastia. However, only my left one was giving me noticeable symptoms, and my main complaint was/is pain. Like you, I noticed that most people don't really complain of pain very much when it comes to this disorder, especially in older, overweight men. Most of the time, the main complaint of people is simply that the breast tissue is growing.
My tissue is definitely growing, but pain is my main complaint. I'm older so I don't really care about having a saggy boob. But I do care about pain and it's pretty much all the time. My other big complaint is a feeling of fullness under the breast. I can literally feel a lump under my left breast when I'm just walking around or sitting in a chair. It feels like a marble underneath the skin. The combination of the foreign body in my breast, the increased size, and the pain is very disconcerting because it never goes away. Anytime I flex my chest it hurts. If I get out of a recliner, it hurts. If I turn over in bed, it hurts. It hurts if I make any type of sudden movement that require chest muscles. I have not heard of this from anyone else with gynecomastia, so it makes me wonder if mine is somehow different than everyone else's.
Apparently, others do not have this type of pain with their gyno, which makes me wonder why I do. Unfortunately, no one can answer this question. My doctor and I have not been able to attribute a medication to my gyno, and that's often a major cause in men who don't use drugs/steroids. I'm waiting to get my hormone level results, but in all probability, there will be no problem. My physician said it was a "shot in the dark".
It has been said that there is ALWAYS a cause for gynecomastia, however, 25% of the time, no cause can be found. It would be nice to know what the prognosis is for older males with gynecomastia, but no one can answer that....at least for an older male. Apparently, even in older males, it goes away on it's own sometimes. If it doesn't go away, I don't know if it will keep growing and being painful forever. Even the experts cannot answer this question. I've noticed that most doctors don't really seem to know much about the condition, which is kind of surprising, considering it's so common.