From what I know, my basic knowledge says that if you are sleeping every night under a beam or if your house has multiple beams, then Vaastu will not be good probably. False ceiling is not so much of a problem I think and there are specific Vaastu remedies that you can take in consultation with an expert to reduce the impact of negative energy. Vaastu science states that beam is negative since it will create differences in opinion amongst family members or residents, build up stress and lead to chronic pain in the shoulder and head without any clearly visible factors and also lead to lower productivity while working. If a beam is over your head in the bedroom, it may also lead to frequent headaches. Sitting continuously under a beam for more than 8 hours may lead to more negative impact also.
More than anything, false ceiling actually helps in neutralizing the negative impact of a beam by hiding it. Other remedies including placement of two Vaastu wooden steps on both sides of the beam that face each other. Wooden pyramid can also be placed on the side wall of the beam. The beam is hidden by the false ceiling which is a good move in my opinion as I said and you should avoid working/studying under this overhead beam as much as possible.