First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
The symptoms you describe are consistent with essential tremor (ET), which can effect the head, the limbs or the voice. The most common is the head, and many patients do not notice their head is shaking until they are told. There are 2 medications that are the standards for treating ET, propanolol (which you are on PRN) and primidone (an anti-seizure medication). There are also 2 newer medications that are being used to treat ET, which are Neurontin and Topamax (that are also anti-seizure medications). There has also been some moderate sucess with Botox injections and even brain surgery (deep brain stimulation) for medical refractory cases. Deep brain stimulation seems to work better on limb tremors that head tremors.
I would recommend that you take the Inderal (propanolol) daily and if needed add primidone. If these do not work then you may give a trial to neurontin or topamax. Most tremors do not go away with medications, but can be reduced by 50-60%, that can significantly improve your quality of life.
I hope this has been helpful.