Can you be forced to come into work even after receiving a Dr excuse.?

No, you cannot be forced to go to work. Yes, you can be terminated for not reporting to work - even with a doctors excuse. Only if you are a FMLA-eligible employee and the illness or injury is part of an existing FMLA case or filed as a new one are you protected.

However, this is not an illness or off-the-clock injury. You were injured at work and this is now a Workman's Comp case. Whoever treated you at the hospital should have asked you if this was work-related and you should have answered yes. If you were diagnosed with a concussion and placed out of work by a doctor, your company will be in SERIOUS trouble if they terminate you and if they don't follow the Comp laws of your state. You may need to get yourself a Comp attorney, but I would look for an attorney that does not just do comp cases, or that's all they will work on. You want one that will treat comp separately and deal with the employer separately, to sue them for possible negligence, and pain and suffering if they were negligent, and making them pay for terminating you. A comp lawyer won't do any of those things.

So you text your boss and tell him to get the Workman's Comp paperwork started, that you will not be back to work until your doctor clears you, and if he has a problem with that, then start looking for a lawyer.

You need to file a workers comp claim immediately. They cannot fire you for doing so. If your doctor says you can't work (and you certainly shouldn't if you have a concussions), you can't work. They cannot fire you while a WC claim is processing or while you are out due to an accident at work. I hope you told the doctor exactly what happened. Your employer could be in big trouble for denying you medical attention.

Yes, they can fire you and if they do you can file a complaint with the Department of Labor and let them decide if it was justified.

No, but might get fired.

They can't make you work but they can fire you. Why didn't you go to the nearest hospital? It's better than driving forty miles home and then seeing a physician.

They can't physically force you. They can fire you.

Whenever you are injured at work, then your boss should have sent you to the ER to be checked out. Also with any injury at work, then you (might) have been eligible for WC, which would pay for any medical treatment for this injury or any follow up treatment and (possibly) after a few days or a week waiting period (might) be eligible for lost wages.

But, even been forced to work, you should have gone to the ER (before) driving 40 miles home. A concussion can be serious, thus driving home 1st and then seeking treatment was stupid. The DR excuse could be (not) taken serious, since you failed to seek treatment asap.

So, yes he could fire you for failing to show up at work with this DR excuse, if in fact he does not take it seriously. Now, (if) this concussion causes more problems at work, then you might have a valid reason not to work.

Now, if he were to fire you, then may have a case to file for UI benefits.

You drove 40 miles HOME instead of to the hospital? That was your BIGGEST mistake. Your first mistake was not forcing the issue and going to the hospital when it happened. Based on these mistakes I'd say they are not going to be found in any way liable for your injury and that means they have no reason to keep you around if you can't work.

No one can force you to work.

You can force yourself to work by not wanting to lose your job, but that's your choice.

This is capitalism, baby, and this is part of why it is killing us.

unless you have a written employment contract, you can be fired at any time for any or no reason. HOWEVER, I don't know what the precedent in PA is under state laws and rules. For that, you'll need a PA employment law attorney.

since you obviously don't want to pay for that, I suggest google for PA employment law specifying illness