Hi Owledge,
First of all cant you contact the shaman you were taking ayuscha with somehow and discuss how you feel?
To answer some of your post:
...
'Now how would an opening like that be different for someone where the lower chakras need some work conpared to someone where they are on the same level of development?
And what chakra is most important for balancing out that state? Is it the heart? Or is balance of all chakras more important?'
...
This all depends on a person as everyone has different emotional/psychological make up, acordingly one needs to adress different issues which may corespond to different chakras. I would say that keeping the heart 'polished' has capacity to sort everything out and this is one of the reasons why many schools do orientate on heart predominatley.
As the Sufi saying goes'opening the eyes of the heart'.
It seems however as if you already have the knowing of what needs to be brought up to light and adressedin your process :'a tough fear barrier'.
It wants release .
The way I deal with my issues is by energetic practises, meditation , maybe some physiacal excersise if needed and by asking similar questions:
What is the fear made of emotionally, energetically, or even physiacaly?
Where does it come from? Is this fear mine?
Do I need to act upon it?etc..
Dealing with ones own fear is very grounding and fundamental,as the pshychic block in the stomach gets dissolved and energy circulation changes. Mind ,energy and breath are very closley related.
Passing through this 'gate'is not to be understimated.
Dont know wherther that helps at all, hopefully you will get some sort of answer/inspiration that resonates with you from someone.
Wishing you best.