How Long Should L Wait Between Robaxin 500mg 1/2 And

How long should l wait between Robaxin 500mg 1/2 and Naproxen 220mg to take each? I have severe nerve pain in Hangmans' Fx of neck. My Dr gave me Prednisone 20 mg po Fri. She checked me in office. Today she said to try Naproxen 220 mg. Also have bad spasms in back much of the time. Trying ice pack. No burn today from ice.Also have osteoporosis which is worse.