Thanks for providing more information.
I understand your concern about your persistent back pain.
As per your description,possible differential diagnosis may include repetitive muscle strain due to poor posture,Spondylosis,Nerve compression.
And as you are suffering from last few weeks with little relief so in my opinion you need to be seen by an Orthopedist for a clinical exam and undergo X-ray/MRI of spine.
Numbness,weakess in arms and legs can be associated pressure on nerves at their path.
Vitamin B 12 deficiency,Diabetes can also result in numbness,weakness in extremities.
So your blood sugar levels should be checked.
You should try multivitamin supplement containing B complex.
Also take OTC Motrin,do massage with analgesic ointment and apply warm compresses on back with a heating pad.
Physical therapy can be effective.
Do stretching exercises.
And make an appointment with your doctor.
Hope this helps.
Please rate me high if you are satisfied with our conversation.
In case you have further query press reply to expert button.
Bonus and positive feedback are appreciated.