One of my eyes sometimes involuntarily turn inwards, causing double vision. Should I go to the doctor?

Yes. Double vision should be evaluated to check for the cause. Intermittent esotropia may not be a problem, but best to determine that with an eye care provider first -- may be a peds or neuro-ophthalmologist.
Yes. You have an intermittent esotropia. The cause needs to be determined by your ophthalmologist.