Pictures will help.

Cracks in concrete are not uncommon and not necessarily indicative of a foundation issue. If they don't promulgate and depending on where they originate, they are usually not an issue.

If cracks are deep then may be you have to go for foundation. Because this may create problem for you.

I do agree with Lauren you have to go for foundation, otherwise in future it may also create problem for you.

I'm in FL too, and most of our homes are built on sand. If you are in So FL, that may not be true. Most homes get "patterned" cracks on the exterior walls due to shifting sand and baking sun. It's not indicative of a problem, it's a normal occurrence.

I've not seen just a crack at ground level--that's probably where the concrete blocks meet the foundation. If these are hairline cracks, painting over them with elastomeric paint will fill and cover the crack. Brush above and below and then put 2 coats of paint over the crack and feather it out to the upper and lower areas. If it is a bigger crack, fill with calk and paint over it, again with elastomeric paint.

Down here, exterior cracks are a fact of life. The sun bakes our exterior walls and that causes cracking between the concrete blocks. The good news is that it does not cause cracks inside the home. We've been here on the beach for 13 years and have repaired our share of exterior cracks--always on the south side of our home. We've never seen an inside crack, which would indicate a more serious problem.

We do have unique problems down here, don't we?? Good luck!

May be that area is getting wet.