My mother is anemic and feels light headed and had chest pains when she walks up the stairs ?

She needs: Further evaluation as her chest with exertion could represent angina or worsening anemia.

Supply and demand: Mismatch . Your mom has low level of hemoglobin which is tasked with oxygen carrying to the rest of the body . The total amount of oxygen in the blood is low even though the hemoglobin is fully saturated with oxygen . When there is exertion , there is more demand for oxygen which can not be met . As result your mom feels short winded

Notify your doctor: Chest pain with ambulation could be related to heart disease & her doctor should be notified for evaluation; it may be angina. Light headedness could be again related to a heart condition or else. If anemic enough, patients may feel light headed & fatigued. The fact that with ambulation she has chest pain is concerning & her doctor should be notified. She needs to undergo work up.