Can a manager suspend me and then fire me the next day?

Yes, this is legal to do, assuming you do not have a specific contract for employment. They could have just fired you instead of suspending you,...

Do I have a case if I was hit from the back by someone uninsured and I apparently was uninsured as well according to my insuran?

Sounds like you need to start with talking to a supervisor with your own insurance to figure out if they properly denied coverage.

How should I go about recovering just over $13K in debt from a shady past client? He has been toying with me for over 2 months.

You could sell the debt to collectors, or at this point, file a lawsuit. If you ask for under $10k, you can go to small claims court.

Can a person just because they work in a store assault you and then have you arrested for assault?

This would be up to the district attorney as to any charges. Otherwise, no, they cannot just assault someone just because they came in the store....

Can I have the contractor I am hiring fix my deck before the claim is resolved in Small Claims Court?

You can always ask them to, but there would be no way to force them to.

Checks are routinely sent by the insurance companies and attorneys. I would say they are no more or less secure than an electronic transaction,...

There are a lot of factors or hurdles an employer has to clear before being able to enforce one: https://www.oregonlaws.org/ors/653.295

My employer used physical force and intimidation to reprimand me. Do I have a case?

You could also have a case for false imprisonment if she wouldn't let you go, which sounds like what you are saying.

I've just had a shoulder surgery and now, my other shoulder is hurting really bad from compensating and physical therapy.

Talk to your PT person, and make sure they note it in their file that it is related to the injury to the other arm.

Can I sue my employer

If I recall, the worse punishment is a fine by the IRS of $35. More importantly, it might be in the mail. Many times they are simply sent late. Try...