You are experiencing head pressure since 2 days which is moderate in nature felt on the right side of the head. This condition may be due to Anxiety. If not, it may be due to other causes like Sinusitis, High Blood Pressure, tension headache, Migraine, Stress brain tumors. You also mentioned that you were subjected to Vertebral column surgery (L4 L5) and also you are overweight and sedentary. Spending time either sitting or lying, unless you involve certain type of activity, you might experience these types of symptoms now and again. Try to see your Doctor who can examine you in detail or might subject you to certain investigations to rule out any possible causes and treat them accordingly. If not he might refer you to a particular specialist. Nearly 5-6 thousand causes bring out Head pressure. So you should not worry about these things. You cannot pinpoint only on a particular problem unless you undergo certain basic tests like complete blood tests, CT brain, MRI brain, and Blood pressure evaluation to rule out important causes. Hence treatment depends on the underlying problem or cause. You can use tablet paracetamol twice a day after food for a week to relieve the pain. If it worsens, consult a physician. Hope this helps.