I Have Been Having Severe Spasms Starting From My Bottom

I have been having severe spasms starting from my bottom of spine and it immediately goes up the spin, in spasms, up into my lower head. Lasts only a minute or two, but takes my breath away. Occurs upon sitting or laying down. Side note: I am on prednisone and zpac for bronchial pneumonia. Coughing and hard to breath. I have been on meds for 3 days. Spasms just started today. thank you, Doreen