take some leaves to a local garden center to define whether a bug or disease is involved ....

if no bug/disease.. then have a soil test done ....

without a picture.. and with a lack of tangible facts. its is REALLY hard to help you ....

frankly .. we dont even know if they are potted or in the ground ... more facts please ...

ken

Leaf deformation is most often associated with sucking insects, especially on new, tender growth. Aphids, mealy bugs, scale and mites are all types of sucking insects. Aphids and scale seem to be extremely common pests on citrus, also. I'd examine the plant closely for indications of these pests - often you will notice a sticky substance on the foliage or a black powdery residue. This is honeydew or insect excrement and the black powdery residue is sooty mold, a fungus that grows on the honeydew. Taking a sample of both the insects you find and the damage they cause to your local extension office or full-service nursery should help you identify the problem, since you are unable to post photos here.

There are all manner of controls for these insect problems, ranging from chemical and/or systemic to natural/organic. Generally the recommendation is to start out with the method that offers the lowest toxicity and move up as necessary. Often a strong spray of water will dislodge many insects and repeated applications can keep them at bay. Neem oil is also an effective and extremely low toxicity control.

FWIW, insect/pest problems seem to escalate or become more of a concern when a plant is stressed for whatever reason - drought, poor drainage/too much water, poor or infertile soils, improper lightening/placement, crowding, etc. The insects are often a secondary factor to a plant in poor health. Making sure you are offering optimum growing conditions can go a long way in reducing any insect or pest problems.

In SoCal, the most common culprit responsible for deformed citrus leaves is aphids. (At least that was true up until I left 10 years ago.)

Since then, citrus leafminers have been added to the list.

So, to help you, we either need a detailed description or a photo.