I'm sorry to hear about your back pain after lifting something on your left side. This type of pain is often due to muscle strain or minor injury to the muscles or ligaments supporting your back.

Here are some steps you can take to help manage the pain:

• Rest: Avoid heavy lifting or strenuous activities for a few days to allow your muscles to heal.
• Pain relief: Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) like Naproxen can help reduce pain and inflammation. However, these should be taken as directed by a doctor, considering any personal health conditions.
• Apply ice or heat: Applying ice packs in the first 24-48 hours can reduce inflammation, followed by heat packs to relax muscles.
• Gentle movement: After initial rest, gentle stretching and walking can help prevent stiffness.

If the pain worsens, persists beyond a week, or is accompanied by symptoms like numbness, weakness, or bladder/bowel issues, it is important to see a specialist such as an orthopedic doctor or a spine specialist promptly.

Please consult a doctor to get a proper evaluation and personalized treatment plan. If the pain is severe or you experience any alarming symptoms, seek immediate medical attention.To narrow down potential causes, we will need some more information.Please tell me your age and gender. I understand that you have back pain after lifting something on your left side.