I have ear infection in left ear & tooth ache on left side, what to do for treatment?

Time for visit: Tooth pain can generate phantom ear pain and vice versa. If your discomfort is not relieved by simple anti-inflammatory meds like Ibuprofen in a day or two, an office visit to your pcp or dentist or both may be needed to sort it out.

See MD/DO first: An upper posterior tooth's roots are into or near the sinus cavity, and an ear infection can create some pain with the tooth/teeth. If you know you definitely have an infection, then an md/do is definitely the first step. The question is also whether the tooth had pain first or vice versa.