So you have Four queries
1. Pain in anus for a week.
2. Proctoscopy is not informative.
3. Treatment given is cap Smith for 10 days which is used for internal hemorrhoids and constipation
4. Is the Doctor hiding some information.
See pain in anus could be due to various reasons like surgical conditions (Fissure in ano, Abcess, hemorrhoids etc) and medical conditions (Stress, constipation, psychological etc)
As prcoctoscopy is not informative, your doctor may be looking for some medical cause.
Next Steps
In your case elaborate medical history may be more informative.
Health Tips
Allay anxiety.
Continue cap smuth, if there is constipation.
Hot Sietz bath.
Proper Diagnosis.