Chakras are said to be whirling pools of energy in our body according to Hinduism/Buddhism. It is said that these chakras can be open, closed or overactive, and depending on their status, they could affect people in different ways. Is there anything in Islam that refuse or accept this? Can a Muslim believe in chakras? (Bonus question: is it ok in Islam to meditate?)
Chakras aren't entirely a religious concept. One may need faith to believe in them, however that would depend on the person; in some cultures, there are cases where representations of chakras actually show results in some way.
And as for meditation, it is allowed and is practiced in Islam. Dhikr, in a sense, is a form of meditation, since you sit and dedicate time out of your life directly to God. There are some who focus during this so greatly with all their heart that they cry during dhikr because they feel God's Blessing. This is in fact considered a form of meditation.
In addition, not all meditation is religious — it can be medical, and it has been proven to improve health in some areas — so you're not doing anything wrong if you meditate. There are many forms of meditation out there, and I suggest you look some up. You'd be surprised at how many there are.