Is this pain from my sciatic nerve?

I’ve had a severe cold for 10 days now and am only now feeling better. For the past 3–5 days, I’ve had a stinging sensation on my right ankle (but no exposure to anything caustic), and now I have a strange rash on my lower right leg (circular lesions, almost plaques). But most concerning is the pain in my right buttock for the past 3 days. It began as an intermittent twinge (it doesn’t feel like muscular pain or joint pain, so I’m guessing that it’s nerve pain). It’s now an unrelenting pain, regardless of position (standing, sitting, lying).

Does this sound familiar to anyone? Sciatica, shingles, and cancer are the top research finds, and none of them are good (to varying degrees).