These symptoms sou--
Nd typical of inactivity for a long time.
You need to start moving and do some bending/extending of the back/ /hips/knees. Start slow ; gradually build up the reps/frequency, so to develop muscles ; get them loose (limbered) so when you do these activities, they are not so painful or tight.
Muscle relaxers may also help, but i believe the exercises to stretch ; strengthen will help more.