These are weird symptoms. Just in case, I'd type in all your foods at fitday.com and see if you are missing or low on any important vitamins or minerals. You could also consider upping your carbs a bit and see if that helps. You don't have to be super low carb to be paleo. If this doesn't go away soon, I'd see a doctor just in case the doctor might actually be able to say something useful about what is going on. (I'm tired of doctors who can't help and I am left to figure it out totally on my own..)

Edited to add: By the way, most meats are good sources of potassium so it's hard to eat a lot of meat and still be significantly low on potassium. HOwever, you may want to consider magnesium as a potential and very likely culprit. Coconuts are fairly high in magnesium which may be why coconut milk helped you, and lack of magnesium also can cause muscle cramps. And there aren't a lot of foods high in magnesium that are also paleo so it's fairly easy to not be getting enough magnesium. Symptoms of magnesium deficiency are wide ranging and many of them sound like what you have. They are:

twitches, cramps, muscle tension, muscle soreness, including back aches, neck pain, tension headaches and jaw joint (or TMJ) dysfunction. Also, one may experience chest tightness or a peculiar sensation that he can't take a deep breath. Sometimes a person may sigh a lot.

Symptoms involving impaired contraction of smooth muscles include constipation; urinary spasms; menstrual cramps; difficulty swallowing or a lump in the throat-especially provoked by eating sugar; photophobia, especially difficulty adjusting to oncoming bright headlights in the absence of eye disease; and loud noise sensitivity from stapedius muscle tension in the ear.

Magnesium deficiency symptoms involving the peripheral nervous system include numbness, tingling, and other abnormal sensations, such as zips, zaps and vibratory sensations.

Symptoms or signs of the cardiovascular system include palpitations, heart arrhythmias, angina due to spasms of the coronary arteries, high blood pressure and mitral valve prolapse. Be aware that not all of the symptoms need to be present to presume magnesium deficiency; but, many of them often occur together.

Other general symptoms include a salt craving, both carbohydrate craving and carbohydrate intolerance, especially of chocolate, and breast tenderness.

If you are going to use a magnesium supplement, remember that magnesium oxide in one study only had a 6% digestion rate so don't get the oxide form which is a very common form.
-Eva

-Eva