Thank you for using Doctorspring. I understand that you are considerably worried about your back ache. First of all, back pain is common in hairdressers and your doctor may be right that this is only muscular pain. But you have not mentioned the mode in which you were treated. Muscular pains improve considerably with proper posturing, analgesia, and most importantly physiotherapy. If you did receive physiotherapy, I'd like to know in what form it was administered.

One more thing of concern is that your pain has increased in severity over time and that you experiencing pain when your intra abdominal pressure increases when you strain at stools or, breath in or out. This indicates that your pain may be due to your lungs or intestines. If your pain comes when you eat spicy food or a high protein meal, it could be due to a peptic ulcer which can be easily taken care of with medication alone.

You may have to undergo an endoscopy, Chest X-ray, Abdominal ultrasound. Reinforce to your doctor the nature of your pain and about it's waxing and waning in relation to food. I'm sure he'll be able to help you. I hope this information is of use to you.