Vedic Jyotishi Shanker ji
If your AK is badly afflicted by malefics then its better to pray to your ishta devata.
If you are getting bad dreams continuously then check with prasna chart whether your AK is afflicted or badly placed
AK cannot be in 6th(disease) 8th(bad karma or daridra yoga) or 12th house(losses and unknown enemies) then also pray to your Ishta devata.
Ishta devata is placed in 12th from your AK in d9 chart..If no planet then take the lord of the 12th house..If many planets then take the strongest like exaltation,Own sign or highest drgree in the order given.
AK cannot be badly placed in d9 as it will reflect your karmas and associated bad luck
Om vyam vyasa devaya namah
Anandamayee 