You wont have any problems with taxation but the real problem lies either on the user you are transacting and on that paypal account you do have.
I don't think so. OP is dealing with a large amount of money that is traded on a day to day basis. Receiving $ 5,000 each day is not a joke and could be subjected to an illegal transfer of money in the eyes of law especially if you are US based citizen.
I am asking only for what to do with taxes and do I need licenses and things like that
I am not a US based citizen but I have done my research to help and give you a bit of information what are the steps on what are you going to do with your taxes based on the information given by @gentlemand.
The links below can be tiresome to follow but I would rather deal with those papers and requirements to avoid such problematic events in the long run.
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The Quick Guide To Money Transmitter Licenses