COPD & Emphysema Support Group
COPD is a progressive disease characterized by airflow obstruction or limitation. Emphysema is characterized by loss of elasticity of the lung tissue, destruction of structures supporting the alveoli and of capillaries feeding the alveoli. Both have symptoms that include shortness of breath, among other respiratory troubles. If you are a COPD or Emphysema sufferer, join...

http://ask.healthline.com/goldcontent/budesonide-formoterol#page2
According to this side effect page, what you have are common side effects that should go away soon. If they do not, tell your doctor.
I have been on Symbicort for 1 yr and a half, and like you, it helps my breathing but do notice some side effects. Sometimes it stirs up my acid reflux and esophogeal spasms and I can't take it close to bedtime or it keeps me up.
I'd check with your doc and see what he/she says. Good luck!