Your upper back pain that is less in the morning and worsens throughout the day could indeed be muscular, especially if it increases with activity or posture. This pattern is common in muscle strain or tension, but other causes like joint or nerve issues can also present similarly.

• Since the pain has lasted about 1.5 months, it’s important to monitor for any additional symptoms such as numbness, weakness, or severe pain that doesn’t improve.
• Over-the-counter pain relievers and muscle relaxants, like the combination in Neorelax MR Tablet (which contains a muscle relaxant and anti-inflammatory agents), may help if prescribed by a doctor.
• Gentle stretching, good posture, and avoiding heavy lifting or prolonged sitting can also reduce muscular pain.

I recommend consulting an orthopedic specialist or a physical medicine and rehabilitation doctor to evaluate your pain properly and guide treatment tailored to your condition. If you experience worsening pain, fever, or neurological symptoms, seek medical attention promptly.To narrow down potential causes, we will need some more information.I understand you've been experiencing upper back pain for about a month and a half, which is less in the morning and worsens throughout the day. Please tell me your age and gender.