Symptoms of Lyme disease?

I've noticed in the last week or two a distinct bulls eye shaped rash on my neck and near my left shoulder develop. I don't remember the exact day I first noticed it but I woke up one morning and it was there. It doesn't itch and isn't painful, it just feels dry. After looking this up the only common suspect in Lyme disease. I don't have any other symptoms of this though, I have no headaches or fever like symptoms, I am not outdoors very much and I live in the Southwest. Could the shape of the rash have any other causes?