I am 34 y/o female & i have ms. i am having sciatic type pain lower back. legs heavy..btm of left foot has pain & neuropathy. am i relapsing?

Possible: These symptoms are compatible with a relapse but you need to rule out other causes (such as lumbar spine) as well. Having one disease does not protect one from another. See orthopedic surgeon as well as your neurologist.

Prob not MS: It is possible, but not likely for an MS relapse to cause pain and numbness in one foot. It is much more often caused by irritation of the nerves in the lower back. This is very often treated with physiotherapy, but you should have someone see you in their clinic before starting the treatment.

Suspect so: If an abrupt change has occurred and lasted beyond 24 hrs in absence of fever or infection, sounds like relapse. But other problems could occur, co-morbidities, on top of MS, so your doctor needs to sort out prior to treatment. Hope you are taking potent MS medication to prevent such events.