Hi Is it first time that  you are getting pain on that side? When was your menses ? If  the pain is spasmodic associated with vomiting most common cause on that side is acute appendicitis. There are other reasons like torsion of ovarian  cyst , stone in right ureter and infections on fallopian tube etc. There can be a mild pain even during ovulation . So if no relief it is better to consult a gynaecologist. All the best