This treatment is being suggested on bases of the information provided. However  I would like to examine & investigate your mother in detail. Rule out Hypertension, Diabetes or any other metabolic disorder. Any way it may be tried, --. Dolokind Plus (Mankind) [Aceclofenac100 mg +Paracetamol 350 mg] 1 tab. OD & SOS. X 5 days. --. Caldikind plus  (Mankind) 1 tab OD x 10 days. (You may need help of your local doctor to get these medicines.) --. Fomentation with warm water. Let the part not be exposed to cold. --. Sleep on a hard bed with soft bedding. --. Keep  no pillow under the head. --. Avoid painful acts & activities. -- .Do mild exercises for affected part. --.(for exercises,take help of a physiotherapist or visit my you tube channel 'Dr N C Gupta yoga simplified') --Do not ignore, let it not become beginning of a major problem. --Do ask for a detailed treatment plan. Kindly make sure, there is no allergy to any of these medicines. --For emergency treatment Contact your family doctor or visit nearest hospital. --Wish you a quick recovery & good health. --I hope, I have solved your problem to your satisfaction.   --Kindly rate the answer. Dr N C Gupta MS (ortho).

Lots of things most probably may be early frozen shoulder

Any breathelessness history,  any history of injury to shoulder,,  diabetic, Rt or left arm,

If it is on left side rule out any cardiac problem. Do physio will help you. Consult orthopaedic doctor. Hot or ice fomentation might help.

Could be tendinitis or frozen shoulder Do you have restriction of movement