I too am in CA....lived most of my life in Southern CA although I'm now on the Central Coast.
A round rash, whether or not there is a "clearing" in the middle, that slowly expands over time, associated with neck pain and other odd aches and pains sounds like CLASSIC Lyme disease.
I'm not a doctor, so cannot diagnose you, but I don't believe there is any other rash that expands like that and can stay with you for many many months. It's called erythema chronicum migrans.
Yes, Lyme rashes can hang around for a very
long time. The tick that bit you might have been smaller than the period at the end of this sentence....the nymphal (immature) ticks are very small indeed.
Please click here
for pictures and click here
for the story of Sarah Olson, who says that her bullseye rash remained with her for 7 or 8 months.
I do so hope that I'm wrong and that you DON'T have Lyme, but Razzle and Traveler are correct, the EM rash is enough for the diagnosis of Lyme, without any bloodwork. Current blood tests for Lyme are very inadequate....at least 50% of people who actually have Lyme are missed due to falsely negative blood tests.
Good luck...and please keep us posted!!
P.S. if you email me, I can send you a list of all of the LLMDs in CA. Just click on the little envelope under my name in the left panel.