Hello there...well headache and limb pain can be because of many factors.... to correctly diagnose it and advise treatment i would need a few answers from your side....
1)Since when your mother is suffering from Asthama??
2)Since when have the headaches started??
3)is it always accompnied with right arm pain??
4)Has your mother suffered from neck pain/tingling in the arms or other joint pains before??
5)Does she get throbbing headache or a dull headache?
6)Does she suffer headache when she has acidity or in an stressful situation?
How frequently does she get headache and arm pain bouts?
Do let me know the answers to these