Oddly enough, your symptoms and mine are identical. The sciatic pain, the anal fissure(s) the continuance of pain (prodromal like pain) without overt signs of an outbreak. I too was tested for Herpes with the herpeselect test, Positive for herpes I, negative for herpes II. I had fever blisters years ago, so I figured I would test positive for HSV I. Most agree that you cannot have herpes I both genitally and orally, that having it orally first lessens or eliminates the possibility of having it genitally. I believe I do have herpes I genitally and orally. I am on 500mg valtrex daily for suppression but still have the anal fissures on and off and still, everyday for the last 7 months now, have either a dull pain, or a burning sensation either in my legs, and face and between my shoulder blades, never all at the same time, one place at a time. It is odd. My suggestion, as I am going to do, is next time I have a fissure (or blister if it is one, kinda hard to see there...) I will get it tested. I have had only one possible outbreak on my penis and that was 7 months ago. There is a thought of post herpetic neuralgia (post herpes pain in the nerves) many claim to suffer from it with varying degrees of duration, from weeks to over a year. It has not been well studied other than as it relates to the shingles. Bottom line, have your anal fissures checked to ensure they are just that and not herpes sores. If they are not, the Doc is correct, if it is, then you have it at both places. The pain will subside, slowly lessening to where its hardly noticeable. I do not know how easily it is to spread herpes I to a partner when it is on your anus and you are not engaging in anal sex.
"Dull sciatic pain" and an anal fissure, particularly when someone has had anal fissures related to bowel function, do not suggest herpes at all. As I have said many, many times, the HSV IgM test result is absolutely worthless. It almost never gives useful information and your positive result is meaningless in the presence of the other test results you describe. (Search the threads for "IgM", "herpes diagnosis", and/or "HerpeSelect test".)
1) Asymptomatic shedding can begin immediately (within days or weeks) of acquiring HSV. Asymptomatic shedding is most common in the first 6 months after infection, then declines in frequency.
2) Prolonged neurological pain, whether sciatic or elsewhere, is not a symptom of genital herpes.
3) Unlike what has been taught and believed over the years, for HSV IgM is not an indicator of early vs late infection.
4) See no. 2.
5) No, herpes symptoms generally are much more localized than you describe.
Bottom line: There is no realistic chance that herpes is the cause of your symptoms, both because you do not describe symptoms that suggest that infection, and because of the negative test result at 6 weeks. (It can take 3 months, but it's usually positive by 6 weeks.) Return to your health care provider if your symptoms don't go away.
Good luck-- HHH, MD