hii mam plzz help me my testastrone is low

low testosterone treatment :
- first you have to consult fertility doctor to do the needed test and determine the best treatment pathway , and the treatment steps are : hormone replacement therapy for 12 months at least , and in case of finding tumors in pitutary gland or testicals or adrenal glands , surgical removal is the treatment option in this case , and besides that ,doctor will advise you to take suppliments for at least 6 months during or after the treatment 
what are the causes of low testosterone ?
1. abnormal production levels 
2. adrenal or pituatary glands tumors 
3. medications side effects 
4. testicular injury or obstruction disease 
what are the needed tests ?
- physical examinations  and blood test and urine test and semen analysis test , and hormones levels and imaging test for adrenal and pituatry gland (CT )