It's really hard to tell from the picture, but a painful rash is definitely a hallmark of shingles.
Here''s info about how to identify shingles:
And info on other conditions that may look like shingles: https://www.webmd.com/skin-problems-and-treatments/shingles/qa/what-conditions-look-like-shingles
If you think, even for a minute, that it could be shingles, I urge you to get medical treatment ASAP. The meds available work best when started as soon as possible - the longer you wait, the less effective they are, and shingles can turn into a very painful condition.
Please let us know how you're doing.