Hello,
Thanks for your query at DoctorSpring.cm
I understand your concern
I have accumulated some points from your history which are helpful in diagnosing me your problem-
-You are heavy weight female.Weight is one of the major factors to create back problems because our back bones are made to lift a specific amount of weight only.If there limit crosses then vertebral bones comes under stress & this stress is reflected as pain.
-You are a smoke. Smoking is one of major factor which leads to weak bone or in medical terms osteoporosis.
-You are having heavy breast.This may lead to back problems due to change in the mechanical axis of the body.
Looking at your complaints it does not look that you are having any neurological problem.But you should do following-
-Stop smoking.
-Start taking calcium & vitamin D supplements.
-Start doing exercises, weight bearing exercises will be more helpful. Strengthening exercises will be more helpful.This can be learned from a physiotherapist.
-Get yourself checked for routine blood investigation including thyroid function tests & vitamin B12 levels.
-Do warm fomentation with help of warm packs over your back.This will relieve spasm & thus back pain.
-You should start reducing weight. This is the most important factor in relieving back pain.
-Mild analgesic can be taken for back pain like Tylenol or in severe pain I used to prescribe a combination of tramadol with paracetamol.
Hope this was helpful
Feel free to discuss further,
Regards

This may be due to spasm at your back or spasm of muscles surrounding the spine which does lead to constriction of blood vessels & such sensations.
Hope this will helps,
Regards.