cramp, spasm, convulsion, twitch
搐 centers on sudden, involuntary muscle contractions: cramping, spasms, convulsions, or twitching.
搐 combines 扌 (hand) with 畜, which likely contributes the sound チク and may relate to the idea of pulling or contracting, as in a muscle cramp.
The hand radical 扌 beside 畜 suggests a hand seizing up uncontrollably, like a cramp or spasm.
For チク, imagine a muscle twitching with a sharp 'chick' sound: chick -> チク, and your hand cramps up.