Hi I have problems Once I start sexual activity...

Treatment of sexual problem:

It depends on the cause, so treatment may include conservative management as doing regular exercise, drinking good amount of fluid daily, good nutrition, avoidind stress, and you have to control diseases as dibetes, hypertension.
If there is no response you can take sildenafil or cialis.

Diagnosis of the cause of sexual problem:

You have to visit your doctor for clinical examination and investigation as CBC  to detect anemia and infection, glucose level, blood pressure measurement, renal and liver function tests, ECG and ECHO for cardiac problems, PSA for prostate problems, urine analysis...etc

Causes of sexual problem:

• Stress and anxiety
• Dibetes
• Hypertension
• Taking medications
• Prostate problems
• Hormonal problems as thyroid and testosterone problems...etc

What i advise you?

You have to visit your doctor for the right diagnosis and management.

What is the treatment of Premature Ejaculation ?
Sleep for at least 6 hours per night, and avoid smoking and other harmful habits. 
To improve the power of erection of the penis, you should eat a well-balanced and healthy diet that contains vitamins and proteins, and you should try to exercise your body on a regular basis. 
You should take multivitamins every morning and consume fish and meat on a regular basis. 
Before intercourse, you can take drugs such as Viagra or use treatments such as Procomil or Lidocaine spray.