I am feeling weakness in my body and back pain...

What is the appropriate treamtment of your condition?
Treatment depends on identifying the cause, so it's recommended to visit your family doctor tp assess your condition, detect the diagnosis and treamtent will be accordingly. In cases of anemia, iron pills and vitamin B12 pills should be taken, and in vitamin D deficiency, vitamin D supplements should be taken. You shpuld have a healthy diet rich in vitamins, proteins and minerals, eating nuts and Seafood. Exercising continuously, exposure to sunlight. Ensuring adequate intake of water during the day at a rate of 2-3 liters per day.

Diagmosis:
You shuold undergo a medical and clinical examination by the doctor, do several tests including a complete blood test CBC to check the level of hemoglobin in the blood, check the level of iron and vitamin B12 levels, check the level of vitamin D, analysis of thyroid hormones TSH, examination of blood sugar to exclude diabetes,  electrocardiogram ECG for the heart, and a psychiatric evaluation may be given.

The possible causes of weakness:
There are many reasons that cause laziness and lethargy in the body, the most important of which are the following

• Anemia
• Diabetes mellitis
• Deficiency of some vitamins such as vitamin D and vitamin B12
• Infection, infection, influenza, and cold
• Thyroid disorders
• Malnutrition
• Lack of sleep
• Stress and anxiety
• Depression

Recommendation:
It's recommended to visit your family doctor for further assessment of your condition.