Hi Colin,
Some considerations:
Don't attach the idea of experiencing pain to your exercises, or having a blockage , a self aware state, or anything. Pain can be something opening, pain can be a blessing of healing, pain can mark a boundary to work with and transform.
Approach each session completely neutral, no history, no future, just the present moment and staying focused on the focus's given. 'No thinking' around that , that is not supportive, constructive or useful. That is simple to say, a lot to accomplish. Don't look for pain or expect pain.
In SFQ, you start out by building the lower dan tian and building up kidney energy. This is an important foundation for higher center development or opening. Even in higher levels of SFQ, you spend significant time in the lower dan tian. Your higher center development is directly related to your lower center foundational energy. The stronger your lower foundational centers, the more wisdom you can receive or hold, the more healing power and love you can channel to help others. Just developing, say the brain(sun gazing?), is not as good as developing the lower dan tian relative to 'then' developing a higher center like the brain or third eye. If I had one sense of stressing something, it would be for you to focus more on your lower dan tian. Especially relative to experiencing pain , or any past practices that didn't develop that ground/foundation. See if you can make your focus stronger, seeing your lower dan tian very bright in response to discomfort. Develop that focus. See if you can sort of absorb all else in that lower focus. Sink the energy down. Whatever the energy experience is. Feed it all to your lower dan tian.
You can repeat, " universal energy to my lower dan tian", with each breath to help you stay focused. No rush, slow it down. You could repeat, " universal energy and divine light to my lower dan tian", and see that additional light come in. Again, slow everything down, sink the energy, or your sense of energy within your body/feelings. Heart is feeling, it is heart height, thinking is head/head height. Most of the time we feel and think. Your response to your active is feel and think. Try sinking the energy and focusing there. Apply visualization( very bright), sound, ohm, or repeating as I said,,, communicate with the lower dan tian, to help you build foundational energy to help your heart center opening.
Reapproach doing active. One of many possible approaches: A minimal set could be bouncing, just the starting standing position with passwords, stand, just breathing into the lower dan tian, then harvest qi. This can be a very nice set, if you stand a bit. Standing can be very powerful and grand. You stand at the beginning of creation. As long as you breath into your lower dan tian, you accomplish good foundational work. From there,as you progress, you could add just one exercise from level I. Try different ones, alone for your whole session. If you are more sensitive to one, that is probably the best one for you. Again, pain can be opening, not necessarily blockage. A center developing..
Active exercise is like walking. Let's say my heart is weak, or I have hypertension, or any physical heart issue. Active exercise, done with common sense, just like walking, is good for the heart. You wouldn't stay away from active exercise, or walking, due to a weak physical heart either. In general, if I did have physical heart issues,I might just change my hands to being more palm down, again, to lower energy, direct energy down. I might spiral/pat energy into my heart here and there with my palm like in level II, to feed my heart, calm down my energy if I am feeling some fatigue or tension there,,,putting in a message too. Anxiety sort of rises too. Again, lowering, calming , slowing down, focusing down. Anxiety effects the stomach system, the stomach can swell and create pressure on the spine as well as the heart. Feed it all to that lower caldron.
No matter what goes on for you, heart center opening, or heart blockage, active exercise is an essential ingredient to self healing and transformational growth. Engage with it, try different combos. Baby steps if necessary, a few minutes, build on it. Don't back off when experience happens, engage and work with that energy. Learn level II at some point too. MOre tools, more perspectives to know and apply, more self confidence to be gained.
Again, my overall sense is that you would benefit from lower dan tian focus, body focus, active. That is my main response to you. Relative to what you experience, and where you are coming from. love, gallen