If your story is that they took you to the hospital and the examine didn't reveal anything and you're complaining about injuries that nobody can verify, you have very little chance of winning if nothing is verifiable. You're making many allegations that seem very implausible and unverifiable considering the claims of harm.
Besides the whisper of racism, it seems it was standard procedure based upon the officer's perception. You could probably file a complaint but it would probably get dismissed based on these facts.
This is just my opinion and not a comprehensive answer. You assume the risk because this answer may not apply to your situation depending on the facts.
You can make a complaint about excessive force to the Oakland Police Dept, Internal Affairs division. They will investigate your charges of improper tactics and racial bias. A claim of physical injury is just one factor in such an investigation and it is quite possible that charges of excessive force will be sustained even without significant physical injury. Not every sustained complaint of excessive force is a sound lawsuit. If you think the police acted out of racial bias, you should consult with an experienced local civil rights attorney or law firm, preferably one specializing in police misconduct cases. They will have the ability to evaluate whether your potential case should be brought as a lawsuit.
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