I just want you to know that I also experienced night sweats when I was around 40 (I'm 43 now), and realized that I was in the midst of perimenopause. I was also having other related issues, such as really heavy periods. So my gynecologist put me on a birth control pill, and the night sweats and other symptoms magically disappeared.
I think the key here is getting your hormones checked to see what your levels are. Definitely have someone take a closer look at the lump on your leg -- it will make you feel better, rather than just being brushed off by a doctor who obviously isn't really listening to you. There are plenty of good, easily approachable doctors out there who will be genuinely interested in your well-being. Doesn't sound like you're seeing one of those now.