Thank you very much for the useful information Adam. I have seen the picture closely.
Well if you had chicken pox in the past, you are EXTREMELY UNLIKELY to have it again (as the recurrence of chicken pox is extremely rare).
Moreover, chicken pox does not persist for such a long duration (4/5 weeks) rather the lesions start to heal up and slough off after 2 weeks.
I would consider other causes for these bumps as well such as;
Bacterial infection (staph infection is a common cause for such kind of bumps in the area you described)
Shingles (as they can involve more than one dermatome ---- a person who had chicken pox in the past can have shingles); one thing against shingles in your case is that these bumps are not causing significant pain (shingles give very severe pain) and the lesions are short lived.
Acne is another differential here. Yes you can have acne lesions in this area.
And finally, this can be an allergic reaction to particular kind of garments, soap or other irritants.
Right now you should take tablet claritin (available over the counter) for control of itching.
Can also apply Calamine lotion over the affected area for soothing effect.
Can use topical neosporin ointment and see how you respond to it.
If this persist, does not improve, or get worse, you would require a consultation with a dermatologist for a comprehensive clinical examination; and probably a round of oral antibiotics as well (if this turns out to be staph infection).
Keep the affected area dry and clean.
Use pure cotton under garments.
Use hypoallergic baby soap and avoid scented toilet papers.
Goodluck and get well soon :)
My goal is to provide you with Excellent Service - if satisfied with the response, Please do not forget to Rate my service as this is the only way i get credit for my time and expertise on your question.
If you feel you have gotten anything less, please reply back, I am happy to address follow-up questions.