Today I was fired from my job without any good reason (in my opinion). I would like to know if a company can just fire you without reason.

Great question!   Most employees are "at will". You can quit. The employer can fire you. No reason necessary unless your union contract, the civil service laws, or a private employment contract you negotiated with your employer states otherwise. Assuming these don't apply, no reason is a good reason.   If you are still doubting this go on YouTube and type in "employment law reality check". I think I have posted a dozen or more very short video clips which will help you. All of the common law doctrines such as Master Servant, Faithless Servant or Duty of Loyalty apply in New York. What that means is that you have to please your employer and co-workers. If the employer gets more than one complaint about you from a couple different co-workers you are probably not going to last much longer. Remember that you have to be civil to your manager and fellow employees. Your manager does not to any employee: unless they are discriminating. And you need a plausible theory to prove that.   Make sure you honestly get your unemployment benefits. It's tough not to receive them in New York. If you are denied unemployment it means you need to reflect on whether working for others is your best fit. You might decide to open your own business? Which many many people are doing every day because many manual labor jobs are disappearing quickly.