Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
It seems like you unfortunately have a meningioma that has been determined to be inoperable. You have been experiencing neck stiffness and arm and leg symptoms. Without the ability to examine you and obtain a history, I can not comment on the exact course your symptoms are expected to take nor on their cause. However, what I will tell you is that meningiomas typically grow slowly, though rarely they can grow rapidly or have growth spurts. There is no way to predict the rate of growth of a meningioma.
I suggest you always keep your physicians who follow your meningioma informed about your symptoms. This will allow your physicians to determine whether or not they are caused by the meningioma or if there is another cause. Also, certain medications are available for the treatment of pins-and-needles sensations should this be necessary.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck