The IRS has limited to no staffing at its regional offices. If CA is not yet allowing persons to work in non essential businesses, there may be no one in the IRS office. The IRS has not processed mailed returns for some time. They have not said when they will start processing them again. So your return may be like many others sitting in stacks in trailers unopened. Neither you or the IRS will be able to track the progress until they actually open your return and start processing it.
When they do, you can track it at the IRS tracking web site: https://www.irs.gov/refunds