hello doc. i just want to thank you for what you are doing...
Since your doctor has suggested an HIV test, you should do it. If s/he thought it was a high likelihood you had HIV, it wouldn't have been a mere request; s/he would have more or less insisted. Undoubtedly s/he is just being careful and complete in working up your problem. And with the sexual lifestyle you describe, it is almost impossible that you have HIV.
And if it turns out you actually have HIV, of course you need to know it in order to have proper medical care for the problem. There is no other rational choice, and I have zero patients with not testing for fear of the result. Intellectually, you know that's dumb and you need to get beyond the emotion and think objectively about it.
1-3) This doesn't sound like HIV to me. Perhaps HIV sometimes causes isolated muscle wasting, but I doubt you have HIV wasting syndrome, which usually implies someone very sick in many ways; in particular, you probably would have fever and almost certainly other symptoms as well. Fat redistribution is primarily a side effect of anti-HIV therapy, not HIV infection itself.
4) I have not seen or heard of HIV presenting this way. But I don't provide ongoing care to HIV infected pesons, so I cannot say much more about it.
5) Since your doctor recommended it, you should have an HIV test. You can expect a negative result.
You should ask all these questions of your endocrinologist, and trust his or her replies more than my own.
Best wishes-- HHH, MD