Hello
As you mentioned that pain is in the right flank and on a fix spot , this type of pain may be due to these reasons , these include.
1
Acute appendicitis as this type of pain is a characteristic feature of chronic
appendix , as 12 hours passed so it may turn into chronic form . Diagnosis can be confirmed by physical examination by a doctor ( Pain at McBurney's point) . Also get in
ultrasound of abdomen to rule out appendix.
2 The next reason of such pain may be right renal calculus . Diagnosis can be confirmed by ultrasound of
kidney ( concerned ) . However stone in
urinary system anywhere on the right side may cause such type of pain . Sometimes this type of pain also radiate to the back.
3 In FEMALE patient such type of pain may be due to
ovarian cyst or
salpingitis . Diagnosis can be confirmed by ultrasound .
4 Amoebic
colitis or ulcer in colon may be the next reason of such pain .
Colonoscopy rule out this type of pain.
In my opinion at present consult a physician/ Surgeon and rule out appendix and deal as mentioned above.
Hope this information will help you.