You need to take your child to his doctor. These are not the signs of reflux in an infant. While your baby is young still, these might be the signs of illnesses that begin in infancy. If your baby is eating enough, gaining weight, doesn't appear to have an acute illness (i.e. these symptoms are not brand new over the past couple of days), please consider doing the following:
Monitor your child’s development. Keep an eye on when/if your child is hitting the key milestones. Write them down. Here is a list of developmental milestones your baby should have reached and should be reaching in the near future.
Make an appointment for the doctor if you don't have one coming up soon. Babies develop at different rates, so you don’t need to panic if your child is a little late here and there. There’s a wide range of “normal.” But if your child is not meeting the milestones for his or her age, or you suspect a problem, share your concerns with your child’s doctor.
Don’t accept a wait-and-see approach. If you are told by your doctor to just wait a few months, make sure to agree on a plan: if he's not doing such-and-such a thing by the next visit, what will happen? Are there tests or is there a specialist the baby needs to see for a second opinion? Don't just wait. You are your baby's advocate. Ideally so is your baby's doctor, but even well-meaning/good doctors miss red flags sometimes.
Trust your instincts. I can't emphasize this enough. In many studies, the parents (especially the mother) will know there's something wrong with their child before the doctor(s) diagnose a problem. If your gut is telling you something is wrong, be persistent.