rowuk

I think the term open or closed is confusing. Your throat cannot open or close except with sleep apnea. You may be playing tense or be grunting/singing while playing. The former is caused very often by bad breathing habits. You need to inhale, then IMMEDIATELY exhale without holding the air in. This needs to be very intensively practiced.
Grunting or singing involves the VOCAL CHORDS doing undesirable things while playing. Curing this is tougher. A good teacher can help a lot here. I do not know of any successful self help methods except practicing VERY slowly and watching in a mirror.

__________________
Whenever I feel blue, I start breathing again.