Hi and Welcome:
Unfortunately, as we are not doctors, we cannot say if your symptoms may or may not be Lupus. What you describe does sound like symptoms related to some sort of AI or Connective Tissue issue. But, we cannot even say that for sure.
You mentioned a rash; please know that there are many different types of rashes in Lupus. Including, but not limited to: The butterfly rash, Subcutaneous lesions (two types: red pimples or flat lesions), discoid lesions, and a host of Non-Specific rahses/lesions). I am not saying that what you experienced was a Lupus rash, but do not dismiss it as not being a Lupus Rash if indeed you are diagnosed with Lupus.
Joint pain as the first and primary symptom is not always true. Lupus affects each of us differently and, as such, our first symptom (or our primary symptom) can cover a broad range. For some, the first symptom is the rash; for some it is damage to internal organs; for some it is extreme fatigue. I could go on an on about what our first symptoms are. The point being, there is no set of symptoms that are a standard as first and primary for this disease.
Perhaps you can read some of the "stickys" on the top of each forum, especially those dealing with Lupus Diagnosis and Treatments. It might be beneficial for you to acquaint yourself with those so that you can speak with your doctors about running the appropriate tests in order to determine what the underlying cause of your symptoms might be.
I wish you the very best and please, keep us posted.
Peace and Blessings
Look For The Good and Praise It!