I feel as if I am holding my breath. My heart rate is extremely slow for 5-10 beats then it speeds back up to normal. What causes this?

Arrhythmia. Heart rate does gets slower and faster with different phases of respiration called sinus arrhythmia, it is not a pathological problem it does gets pronounced with aging, we can say part of aging changes. I do not know your age, so have yourself checked out to make sure you not having any other pathological forms of arrhythmia.

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My stress test came back with significant shortness of breath and inadequate heart rate recovery. Are these findings normal cause doc did not followup?

Sob. You should discuss the test with your doctor and ask what the interpretation of the test is. Shortness of breath and abnormal heart rate recovery can be signficant findings even if the ecg remained normal. They can also relate to just being 'out of shape'. You doctor should be able to explain about this to you. Read more...