It is spirit harm. You need protection from Hayagriva. You need to make an offering to a stupa, by painting it white and saffron. This is quite a common method for success and healing. I do this normally anyway on Buddha’s special days, so I’ll dedicate the action to you on this special day of the anniversary of Buddha’s turning the wheel of Dharma, when the merit of whatever virtuous activities one does is multiplied 100 million times.
Then, recite the Vajrapani Hayagriva Garuda mantra. Visualize yourself as the deity and purify the four things: sickness, spirit harm, negative karma, and defilements.
I will do some pujas. You can write me in five days to say if there’s any change. However, there is no question that what you are experiencing is a sign of purification, because reciting the Heart Sutra is extremely powerful purification. It brings up negative karma and finishes karma that one would have to experience for many eons in the hell realms and so forth. This is a definite sign that you are finishing heavy negative karma, which is manifesting as this health problem. Once you experience this, you don’t have to be reborn in the lower realms, such as hell, and suffer for eons.
Therefore, what happened is very positive.
With much love and prayer...