Food and heat are probably contributing factors as mentioned. Checking the temp of the hot hide compared to the braches might be useful.
Without more details I am uncertain but I suspect that you have a snake that is feeling insecure. Young snakes are very vulnerable to predators and do not like open spaces, such as large enclosures. They are comfortable in small areas with ready access to hiding spots. Transparent enclosures often need to be covered with paint or cardboard for this reason. Hides need to be snug, so they only just fit into in them and therefore feel secure. Arboreal snakes also feel secure on an elevated perch, preferably just below a ceiling.
Different snake species and different individuals vary in their temperaments. A “high strung” snake is one that reacts defensively to minimal stimuli. To change this it needs to be trained to be not so reactive. This can be done through the “man up” method where all behavioural responses to all stimuli are corrected in one. (I do wonder who has to “man up”.) Or you can adopt a one-step at a time approach to gradually altering behavioural responses. Ultimately both methods will likely achieve the same goal. It is up to you to choose the method that sits most comfortably with you. I personally favour the latter and following would be my suggestions…
Having addressed any caging and environmental issues, begin by keeping your interactions to an absolute minimum – basically cleaning and water only. Do not attempt to handle the snake. Bear in mind that handling is not natural to snakes. For a young snake in nature, being held by another animal usually means imminent disaster. So handling a young snake that is already stressed is more likely to compound the problem than alleviate it. However, as Malissa pointed out, they can learn.
Once the snake is looking consistently calm when you access the enclosure, then you can begin. Be patient – the snake will set the pace, not you. Firstly step is to place the snake in deep opaque container, like a plastic rubbish bin, for 10 - 15 mins while you observe from above. Do this three no more often than once every second day until you get little or no defensive reactions. Next step is to place the snake in a clear, shallow container that you can balance on your lap. Again, repeat these sessions until you get little or no defensive reactions. The next step is to place your hands in the container. Allow the snake to come to you to investigate and let it do so without you moving. Once the snake is comfortable investigating you during a session, then gradually begin to increase your interactions until you are at the point of normal handling. Once youcan handle it without incident in the tub, try it without.
You may wish to increase the time duration of handling first or the frequency of sessions per week. Just do one or the other.
A few points…
No jungle gym until you have a confident, comfortable snake to be handled.
Do not handle when coming up to a shed i.e. once eyes go milky until after sloughing.
Do not handle for two to three days following a meal and preferably.
Do not handle is the snake shows obvious signs of not wanting to be disturbed.
Good luck,
Blue