If I Don't Know If I Have Had The Chicken

If I don't know if I have had the chicken pox is it safe to still have the vaccine shot? Also, is there a blood test to see if I have had shingles before? I think I had shingles about 5 years ago and I went to a walk in clinic and they said I had flesh eating disease. The doctor put me on antibiotics and 4 days later I improved some and I went to my doctor who said he couldn't tell what I had. Of course my doctor said I didn't have flesh eating disease. I still have the burning sensation on the same spot to this day. I am considering the shot and booked an appointment for next week but before I have it, I want to be sure that it will not harm me. Thank you .